feat: implement authentication flow

Backend:
- AppConfig, AppError, AppState modules for shared infrastructure
- JWT creation/verification with HS256 (jsonwebtoken crate)
- Session management: SHA-256 token hashing, DB-backed sessions
- Auth middleware: AuthUser, RequireHost, RequireAdmin extractors
- POST /api/v1/join: name-only registration, 4-digit PIN + bcrypt hash
- POST /api/v1/recover: PIN-based recovery with 3-attempt lockout (15 min)
- POST /api/v1/admin/login: bcrypt password verification
- DELETE /api/v1/session: logout (session invalidation)
- Migration 006: user PIN lockout columns (failed_pin_attempts, pin_locked_until)
- Models: Event, User (with role enum), Session with all CRUD methods

Frontend:
- api.ts: typed fetch wrapper with automatic Bearer token injection
- auth.ts: JWT/PIN localStorage management with Svelte store
- /join: name entry form with PIN display modal and copy button
- /recover: name + PIN recovery form with saved PIN pre-fill
- /feed: placeholder gallery page with logout
- Root layout: auth initialization on mount
- Root page: redirect to /join or /feed based on auth state

All responses use German language strings as specified.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/Cargo.lock

@@ -898,8 +898,10 @@ dependencies = [
  "jsonwebtoken",
  "minijinja",
  "oxipng",
+ "rand 0.9.2",
  "serde",
  "serde_json",
+ "sha2",
  "sqlx",
  "sysinfo",
  "tokio",

backend/Cargo.toml

@@ -16,6 +16,8 @@ jsonwebtoken = "9"
 bcrypt = "0.15"
 uuid = { version = "1", features = ["v4", "serde"] }
 chrono = { version = "0.4", features = ["serde"] }
+sha2 = "0.10"
+rand = "0.9"
 anyhow = "1"
 tracing = "0.1"
 tracing-subscriber = { version = "0.3", features = ["env-filter"] }

backend/migrations/006_user_pin_lockout.down.sql

@@ -0,0 +1,2 @@
+ALTER TABLE "user" DROP COLUMN IF EXISTS pin_locked_until;
+ALTER TABLE "user" DROP COLUMN IF EXISTS failed_pin_attempts;

backend/migrations/006_user_pin_lockout.up.sql

@@ -0,0 +1,2 @@
+ALTER TABLE "user" ADD COLUMN failed_pin_attempts SMALLINT NOT NULL DEFAULT 0;
+ALTER TABLE "user" ADD COLUMN pin_locked_until TIMESTAMPTZ;

backend/src/auth/handlers.rs

@@ -0,0 +1,232 @@
+use axum::extract::State;
+use axum::http::StatusCode;
+use axum::Json;
+use chrono::{Duration, Utc};
+use rand::Rng;
+use serde::{Deserialize, Serialize};
+use uuid::Uuid;
+
+use crate::auth::jwt;
+use crate::auth::middleware::AuthUser;
+use crate::error::AppError;
+use crate::models::event::Event;
+use crate::models::session::Session;
+use crate::models::user::{User, UserRole};
+use crate::state::AppState;
+
+#[derive(Deserialize)]
+pub struct JoinRequest {
+    pub display_name: String,
+}
+
+#[derive(Serialize)]
+pub struct JoinResponse {
+    pub jwt: String,
+    pub pin: String,
+    pub user_id: Uuid,
+    pub is_new: bool,
+}
+
+pub async fn join(
+    State(state): State<AppState>,
+    Json(body): Json<JoinRequest>,
+) -> Result<(StatusCode, Json<JoinResponse>), AppError> {
+    let display_name = body.display_name.trim();
+    if display_name.is_empty() || display_name.len() > 50 {
+        return Err(AppError::BadRequest(
+            "Name muss zwischen 1 und 50 Zeichen lang sein.".into(),
+        ));
+    }
+
+    let event = Event::find_or_create(
+        &state.pool,
+        &state.config.event_slug,
+        &state.config.event_name,
+    )
+    .await?;
+
+    // Generate a 4-digit PIN
+    let pin: String = format!("{:04}", rand::rng().random_range(0..10000u32));
+    let pin_hash =
+        bcrypt::hash(&pin, 12).map_err(|e| AppError::Internal(anyhow::anyhow!(e)))?;
+
+    let user = User::create(&state.pool, event.id, display_name, &pin_hash).await?;
+
+    let token = jwt::create_token(
+        user.id,
+        event.id,
+        user.role.clone(),
+        &state.config.jwt_secret,
+        state.config.session_expiry_days,
+    )
+    .map_err(|e| AppError::Internal(anyhow::anyhow!(e)))?;
+
+    let token_hash = jwt::hash_token(&token);
+    let expires_at = Utc::now() + Duration::days(state.config.session_expiry_days);
+    Session::create(&state.pool, user.id, &token_hash, expires_at).await?;
+
+    Ok((
+        StatusCode::CREATED,
+        Json(JoinResponse {
+            jwt: token,
+            pin,
+            user_id: user.id,
+            is_new: true,
+        }),
+    ))
+}
+
+#[derive(Deserialize)]
+pub struct RecoverRequest {
+    pub display_name: String,
+    pub pin: String,
+}
+
+#[derive(Serialize)]
+pub struct RecoverResponse {
+    pub jwt: String,
+    pub user_id: Uuid,
+}
+
+pub async fn recover(
+    State(state): State<AppState>,
+    Json(body): Json<RecoverRequest>,
+) -> Result<Json<RecoverResponse>, AppError> {
+    let display_name = body.display_name.trim();
+
+    let event = Event::find_by_slug(&state.pool, &state.config.event_slug)
+        .await?
+        .ok_or_else(|| AppError::NotFound("Event nicht gefunden.".into()))?;
+
+    let users =
+        User::find_by_event_and_name(&state.pool, event.id, display_name).await?;
+
+    if users.is_empty() {
+        return Err(AppError::NotFound(
+            "Kein Benutzer mit diesem Namen gefunden.".into(),
+        ));
+    }
+
+    for user in &users {
+        // Check PIN lockout
+        if let Some(locked_until) = user.pin_locked_until {
+            if Utc::now() < locked_until {
+                return Err(AppError::TooManyRequests(
+                    "Zu viele Versuche. Bitte warte 15 Minuten.".into(),
+                ));
+            }
+        }
+
+        let pin_matches = bcrypt::verify(&body.pin, &user.recovery_pin_hash)
+            .unwrap_or(false);
+
+        if pin_matches {
+            // Reset failed attempts on success
+            User::reset_pin_attempts(&state.pool, user.id).await?;
+
+            let token = jwt::create_token(
+                user.id,
+                event.id,
+                user.role.clone(),
+                &state.config.jwt_secret,
+                state.config.session_expiry_days,
+            )
+            .map_err(|e| AppError::Internal(anyhow::anyhow!(e)))?;
+
+            let token_hash = jwt::hash_token(&token);
+            let expires_at = Utc::now() + Duration::days(state.config.session_expiry_days);
+            Session::create(&state.pool, user.id, &token_hash, expires_at).await?;
+
+            return Ok(Json(RecoverResponse {
+                jwt: token,
+                user_id: user.id,
+            }));
+        }
+
+        // Wrong PIN — increment failure count
+        let attempts = User::increment_failed_pin(&state.pool, user.id).await?;
+        if attempts >= 3 {
+            let lockout = Utc::now() + Duration::minutes(15);
+            User::lock_pin(&state.pool, user.id, lockout).await?;
+        }
+    }
+
+    Err(AppError::Unauthorized("PIN ist falsch.".into()))
+}
+
+#[derive(Deserialize)]
+pub struct AdminLoginRequest {
+    pub password: String,
+}
+
+#[derive(Serialize)]
+pub struct AdminLoginResponse {
+    pub jwt: String,
+}
+
+pub async fn admin_login(
+    State(state): State<AppState>,
+    Json(body): Json<AdminLoginRequest>,
+) -> Result<Json<AdminLoginResponse>, AppError> {
+    if state.config.admin_password_hash.is_empty() {
+        return Err(AppError::Forbidden(
+            "Admin-Login ist nicht konfiguriert.".into(),
+        ));
+    }
+
+    let valid = bcrypt::verify(&body.password, &state.config.admin_password_hash)
+        .unwrap_or(false);
+
+    if !valid {
+        return Err(AppError::Unauthorized("Falsches Passwort.".into()));
+    }
+
+    let event = Event::find_or_create(
+        &state.pool,
+        &state.config.event_slug,
+        &state.config.event_name,
+    )
+    .await?;
+
+    // Find or create the admin user for this event
+    let admin_name = "Admin";
+    let users = User::find_by_event_and_name(&state.pool, event.id, admin_name).await?;
+    let admin_user = if let Some(u) = users.into_iter().find(|u| u.role == UserRole::Admin) {
+        u
+    } else {
+        // Create admin user with a dummy PIN (admin authenticates via password)
+        let dummy_hash = bcrypt::hash("0000", 4)
+            .map_err(|e| AppError::Internal(anyhow::anyhow!(e)))?;
+        let user = User::create(&state.pool, event.id, admin_name, &dummy_hash).await?;
+        sqlx::query("UPDATE \"user\" SET role = 'admin' WHERE id = $1")
+            .bind(user.id)
+            .execute(&state.pool)
+            .await?;
+        User::find_by_id(&state.pool, user.id)
+            .await?
+            .ok_or_else(|| AppError::Internal(anyhow::anyhow!("admin user creation failed")))?
+    };
+
+    let token = jwt::create_token(
+        admin_user.id,
+        event.id,
+        UserRole::Admin,
+        &state.config.jwt_secret,
+        1, // Admin sessions expire after 1 day
+    )
+    .map_err(|e| AppError::Internal(anyhow::anyhow!(e)))?;
+
+    let token_hash = jwt::hash_token(&token);
+    let expires_at = Utc::now() + Duration::days(1);
+    Session::create(&state.pool, admin_user.id, &token_hash, expires_at).await?;
+
+    Ok(Json(AdminLoginResponse { jwt: token }))
+}
+
+pub async fn logout(
+    State(state): State<AppState>,
+    auth: AuthUser,
+) -> Result<StatusCode, AppError> {
+    Session::delete_by_token_hash(&state.pool, &auth.token_hash).await?;
+    Ok(StatusCode::NO_CONTENT)
+}

backend/src/auth/jwt.rs

@@ -0,0 +1,53 @@
+use chrono::{Duration, Utc};
+use jsonwebtoken::{DecodingKey, EncodingKey, Header, Validation};
+use serde::{Deserialize, Serialize};
+use sha2::{Digest, Sha256};
+use uuid::Uuid;
+
+use crate::models::user::UserRole;
+
+#[derive(Debug, Serialize, Deserialize)]
+pub struct Claims {
+    pub sub: Uuid,
+    pub event_id: Uuid,
+    pub role: UserRole,
+    pub exp: i64,
+    pub iat: i64,
+}
+
+pub fn create_token(
+    user_id: Uuid,
+    event_id: Uuid,
+    role: UserRole,
+    secret: &str,
+    expiry_days: i64,
+) -> Result<String, jsonwebtoken::errors::Error> {
+    let now = Utc::now();
+    let claims = Claims {
+        sub: user_id,
+        event_id,
+        role,
+        iat: now.timestamp(),
+        exp: (now + Duration::days(expiry_days)).timestamp(),
+    };
+    jsonwebtoken::encode(
+        &Header::default(),
+        &claims,
+        &EncodingKey::from_secret(secret.as_bytes()),
+    )
+}
+
+pub fn verify_token(token: &str, secret: &str) -> Result<Claims, jsonwebtoken::errors::Error> {
+    let data = jsonwebtoken::decode::<Claims>(
+        token,
+        &DecodingKey::from_secret(secret.as_bytes()),
+        &Validation::default(),
+    )?;
+    Ok(data.claims)
+}
+
+pub fn hash_token(token: &str) -> String {
+    let mut hasher = Sha256::new();
+    hasher.update(token.as_bytes());
+    format!("{:x}", hasher.finalize())
+}

backend/src/auth/middleware.rs

@@ -0,0 +1,96 @@
+use axum::extract::{FromRequestParts, State};
+use axum::http::request::Parts;
+use uuid::Uuid;
+
+use crate::auth::jwt;
+use crate::error::AppError;
+use crate::models::session::Session;
+use crate::models::user::UserRole;
+use crate::state::AppState;
+
+#[derive(Debug, Clone)]
+pub struct AuthUser {
+    pub user_id: Uuid,
+    pub event_id: Uuid,
+    pub role: UserRole,
+    pub token_hash: String,
+}
+
+impl FromRequestParts<AppState> for AuthUser {
+    type Rejection = AppError;
+
+    async fn from_request_parts(
+        parts: &mut Parts,
+        state: &AppState,
+    ) -> Result<Self, Self::Rejection> {
+        let header = parts
+            .headers
+            .get("authorization")
+            .and_then(|v| v.to_str().ok())
+            .ok_or_else(|| AppError::Unauthorized("Token fehlt.".into()))?;
+
+        let token = header
+            .strip_prefix("Bearer ")
+            .ok_or_else(|| AppError::Unauthorized("Ungültiges Token-Format.".into()))?;
+
+        let claims = jwt::verify_token(token, &state.config.jwt_secret)
+            .map_err(|_| AppError::Unauthorized("Token ungültig oder abgelaufen.".into()))?;
+
+        let token_hash = jwt::hash_token(token);
+
+        let session = Session::find_by_token_hash(&state.pool, &token_hash)
+            .await
+            .map_err(|e| AppError::Internal(e.into()))?
+            .ok_or_else(|| AppError::Unauthorized("Sitzung nicht gefunden oder abgelaufen.".into()))?;
+
+        // Update last_seen_at in the background (fire-and-forget)
+        let pool = state.pool.clone();
+        let session_id = session.id;
+        tokio::spawn(async move {
+            let _ = Session::touch(&pool, session_id).await;
+        });
+
+        Ok(Self {
+            user_id: claims.sub,
+            event_id: claims.event_id,
+            role: claims.role,
+            token_hash,
+        })
+    }
+}
+
+/// Extractor that requires at least Host role.
+pub struct RequireHost(pub AuthUser);
+
+impl FromRequestParts<AppState> for RequireHost {
+    type Rejection = AppError;
+
+    async fn from_request_parts(
+        parts: &mut Parts,
+        state: &AppState,
+    ) -> Result<Self, Self::Rejection> {
+        let auth = AuthUser::from_request_parts(parts, state).await?;
+        match auth.role {
+            UserRole::Host | UserRole::Admin => Ok(Self(auth)),
+            _ => Err(AppError::Forbidden("Nur für Hosts und Admins.".into())),
+        }
+    }
+}
+
+/// Extractor that requires Admin role.
+pub struct RequireAdmin(pub AuthUser);
+
+impl FromRequestParts<AppState> for RequireAdmin {
+    type Rejection = AppError;
+
+    async fn from_request_parts(
+        parts: &mut Parts,
+        state: &AppState,
+    ) -> Result<Self, Self::Rejection> {
+        let auth = AuthUser::from_request_parts(parts, state).await?;
+        match auth.role {
+            UserRole::Admin => Ok(Self(auth)),
+            _ => Err(AppError::Forbidden("Nur für Admins.".into())),
+        }
+    }
+}

backend/src/auth/mod.rs

@@ -0,0 +1,3 @@
+pub mod handlers;
+pub mod jwt;
+pub mod middleware;

backend/src/config.rs

@@ -0,0 +1,43 @@
+use std::path::PathBuf;
+
+use anyhow::{Context, Result};
+
+#[derive(Clone, Debug)]
+pub struct AppConfig {
+    pub database_url: String,
+    pub jwt_secret: String,
+    pub session_expiry_days: i64,
+    pub admin_password_hash: String,
+    pub event_name: String,
+    pub event_slug: String,
+    pub media_path: PathBuf,
+    pub app_port: u16,
+}
+
+impl AppConfig {
+    pub fn from_env() -> Result<Self> {
+        Ok(Self {
+            database_url: std::env::var("DATABASE_URL")
+                .context("DATABASE_URL must be set")?,
+            jwt_secret: std::env::var("JWT_SECRET")
+                .context("JWT_SECRET must be set")?,
+            session_expiry_days: std::env::var("SESSION_EXPIRY_DAYS")
+                .unwrap_or_else(|_| "30".to_string())
+                .parse()
+                .context("SESSION_EXPIRY_DAYS must be a number")?,
+            admin_password_hash: std::env::var("ADMIN_PASSWORD_HASH")
+                .unwrap_or_default(),
+            event_name: std::env::var("EVENT_NAME")
+                .unwrap_or_else(|_| "EventSnap".to_string()),
+            event_slug: std::env::var("EVENT_SLUG")
+                .context("EVENT_SLUG must be set")?,
+            media_path: PathBuf::from(
+                std::env::var("MEDIA_PATH").unwrap_or_else(|_| "/media".to_string()),
+            ),
+            app_port: std::env::var("APP_PORT")
+                .unwrap_or_else(|_| "3000".to_string())
+                .parse()
+                .context("APP_PORT must be a number")?,
+        })
+    }
+}

backend/src/error.rs

@@ -0,0 +1,65 @@
+use axum::http::StatusCode;
+use axum::response::{IntoResponse, Response};
+use serde_json::json;
+
+#[derive(Debug)]
+pub enum AppError {
+    BadRequest(String),
+    Unauthorized(String),
+    Forbidden(String),
+    NotFound(String),
+    TooManyRequests(String),
+    Internal(anyhow::Error),
+}
+
+impl AppError {
+    fn status_and_code(&self) -> (StatusCode, &str) {
+        match self {
+            Self::BadRequest(_) => (StatusCode::BAD_REQUEST, "bad_request"),
+            Self::Unauthorized(_) => (StatusCode::UNAUTHORIZED, "unauthorized"),
+            Self::Forbidden(_) => (StatusCode::FORBIDDEN, "forbidden"),
+            Self::NotFound(_) => (StatusCode::NOT_FOUND, "not_found"),
+            Self::TooManyRequests(_) => (StatusCode::TOO_MANY_REQUESTS, "too_many_requests"),
+            Self::Internal(_) => (StatusCode::INTERNAL_SERVER_ERROR, "internal_error"),
+        }
+    }
+
+    fn message(&self) -> String {
+        match self {
+            Self::BadRequest(msg)
+            | Self::Unauthorized(msg)
+            | Self::Forbidden(msg)
+            | Self::NotFound(msg)
+            | Self::TooManyRequests(msg) => msg.clone(),
+            Self::Internal(err) => {
+                tracing::error!("internal error: {err:#}");
+                "Ein interner Fehler ist aufgetreten.".to_string()
+            }
+        }
+    }
+}
+
+impl IntoResponse for AppError {
+    fn into_response(self) -> Response {
+        let (status, code) = self.status_and_code();
+        let message = self.message();
+        let body = json!({
+            "error": code,
+            "message": message,
+            "status": status.as_u16(),
+        });
+        (status, axum::Json(body)).into_response()
+    }
+}
+
+impl From<anyhow::Error> for AppError {
+    fn from(err: anyhow::Error) -> Self {
+        Self::Internal(err)
+    }
+}
+
+impl From<sqlx::Error> for AppError {
+    fn from(err: sqlx::Error) -> Self {
+        Self::Internal(err.into())
+    }
+}

backend/src/main.rs

@@ -1,7 +1,17 @@
 use anyhow::Result;
+use axum::routing::{delete, post};
+use axum::Router;
 use tracing_subscriber::{layer::SubscriberExt, util::SubscriberInitExt};
 
+mod auth;
+mod config;
 mod db;
+mod error;
+mod models;
+mod state;
+
+use config::AppConfig;
+use state::AppState;
 
 #[tokio::main]
 async fn main() -> Result<()> {
@@ -14,18 +24,22 @@ async fn main() -> Result<()> {
         .with(tracing_subscriber::fmt::layer())
         .init();
 
-    let database_url =
-        std::env::var("DATABASE_URL").expect("DATABASE_URL must be set");
-    let port: u16 = std::env::var("APP_PORT")
-        .unwrap_or_else(|_| "3000".to_string())
-        .parse()?;
+    let config = AppConfig::from_env()?;
+    let pool = db::create_pool(&config.database_url).await?;
+    let state = AppState::new(pool, config.clone());
 
-    let _pool = db::create_pool(&database_url).await?;
+    let api = Router::new()
+        .route("/api/v1/join", post(auth::handlers::join))
+        .route("/api/v1/recover", post(auth::handlers::recover))
+        .route("/api/v1/admin/login", post(auth::handlers::admin_login))
+        .route("/api/v1/session", delete(auth::handlers::logout));
 
-    let router = axum::Router::new()
-        .route("/health", axum::routing::get(|| async { "ok" }));
+    let router = Router::new()
+        .route("/health", axum::routing::get(|| async { "ok" }))
+        .merge(api)
+        .with_state(state);
 
-    let listener = tokio::net::TcpListener::bind(("0.0.0.0", port)).await?;
+    let listener = tokio::net::TcpListener::bind(("0.0.0.0", config.app_port)).await?;
     tracing::info!("listening on {}", listener.local_addr()?);
     axum::serve(listener, router).await?;
 

backend/src/models/event.rs

@@ -0,0 +1,47 @@
+use chrono::{DateTime, Utc};
+use sqlx::PgPool;
+use uuid::Uuid;
+
+#[derive(Debug, sqlx::FromRow)]
+pub struct Event {
+    pub id: Uuid,
+    pub slug: String,
+    pub name: String,
+    pub cover_image_path: Option<String>,
+    pub is_active: bool,
+    pub uploads_locked_at: Option<DateTime<Utc>>,
+    pub export_released_at: Option<DateTime<Utc>>,
+    pub export_zip_ready: bool,
+    pub export_html_ready: bool,
+    pub created_at: DateTime<Utc>,
+}
+
+impl Event {
+    pub async fn find_by_slug(pool: &PgPool, slug: &str) -> Result<Option<Self>, sqlx::Error> {
+        sqlx::query_as::<_, Self>("SELECT * FROM event WHERE slug = $1")
+            .bind(slug)
+            .fetch_optional(pool)
+            .await
+    }
+
+    pub async fn create(pool: &PgPool, slug: &str, name: &str) -> Result<Self, sqlx::Error> {
+        sqlx::query_as::<_, Self>(
+            "INSERT INTO event (slug, name) VALUES ($1, $2) RETURNING *",
+        )
+        .bind(slug)
+        .bind(name)
+        .fetch_one(pool)
+        .await
+    }
+
+    pub async fn find_or_create(
+        pool: &PgPool,
+        slug: &str,
+        name: &str,
+    ) -> Result<Self, sqlx::Error> {
+        if let Some(event) = Self::find_by_slug(pool, slug).await? {
+            return Ok(event);
+        }
+        Self::create(pool, slug, name).await
+    }
+}

backend/src/models/mod.rs

@@ -0,0 +1,3 @@
+pub mod event;
+pub mod session;
+pub mod user;

backend/src/models/session.rs

@@ -0,0 +1,64 @@
+use chrono::{DateTime, Utc};
+use sqlx::PgPool;
+use uuid::Uuid;
+
+#[derive(Debug, sqlx::FromRow)]
+pub struct Session {
+    pub id: Uuid,
+    pub user_id: Uuid,
+    pub token_hash: String,
+    pub expires_at: DateTime<Utc>,
+    pub last_seen_at: DateTime<Utc>,
+    pub created_at: DateTime<Utc>,
+}
+
+impl Session {
+    pub async fn create(
+        pool: &PgPool,
+        user_id: Uuid,
+        token_hash: &str,
+        expires_at: DateTime<Utc>,
+    ) -> Result<Self, sqlx::Error> {
+        sqlx::query_as::<_, Self>(
+            "INSERT INTO session (user_id, token_hash, expires_at)
+             VALUES ($1, $2, $3)
+             RETURNING *",
+        )
+        .bind(user_id)
+        .bind(token_hash)
+        .bind(expires_at)
+        .fetch_one(pool)
+        .await
+    }
+
+    pub async fn find_by_token_hash(
+        pool: &PgPool,
+        token_hash: &str,
+    ) -> Result<Option<Self>, sqlx::Error> {
+        sqlx::query_as::<_, Self>(
+            "SELECT * FROM session WHERE token_hash = $1 AND expires_at > NOW()",
+        )
+        .bind(token_hash)
+        .fetch_optional(pool)
+        .await
+    }
+
+    pub async fn touch(pool: &PgPool, id: Uuid) -> Result<(), sqlx::Error> {
+        sqlx::query("UPDATE session SET last_seen_at = NOW() WHERE id = $1")
+            .bind(id)
+            .execute(pool)
+            .await?;
+        Ok(())
+    }
+
+    pub async fn delete_by_token_hash(
+        pool: &PgPool,
+        token_hash: &str,
+    ) -> Result<(), sqlx::Error> {
+        sqlx::query("DELETE FROM session WHERE token_hash = $1")
+            .bind(token_hash)
+            .execute(pool)
+            .await?;
+        Ok(())
+    }
+}

backend/src/models/user.rs

@@ -0,0 +1,102 @@
+use chrono::{DateTime, Utc};
+use serde::{Deserialize, Serialize};
+use sqlx::PgPool;
+use uuid::Uuid;
+
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize, sqlx::Type)]
+#[sqlx(type_name = "user_role", rename_all = "lowercase")]
+pub enum UserRole {
+    Guest,
+    Host,
+    Admin,
+}
+
+#[derive(Debug, sqlx::FromRow)]
+pub struct User {
+    pub id: Uuid,
+    pub event_id: Uuid,
+    pub display_name: String,
+    pub role: UserRole,
+    pub is_banned: bool,
+    pub uploads_hidden: bool,
+    pub recovery_pin_hash: String,
+    pub total_upload_bytes: i64,
+    pub failed_pin_attempts: i16,
+    pub pin_locked_until: Option<DateTime<Utc>>,
+    pub created_at: DateTime<Utc>,
+}
+
+impl User {
+    pub async fn create(
+        pool: &PgPool,
+        event_id: Uuid,
+        display_name: &str,
+        pin_hash: &str,
+    ) -> Result<Self, sqlx::Error> {
+        sqlx::query_as::<_, Self>(
+            "INSERT INTO \"user\" (event_id, display_name, recovery_pin_hash)
+             VALUES ($1, $2, $3)
+             RETURNING *",
+        )
+        .bind(event_id)
+        .bind(display_name)
+        .bind(pin_hash)
+        .fetch_one(pool)
+        .await
+    }
+
+    pub async fn find_by_id(pool: &PgPool, id: Uuid) -> Result<Option<Self>, sqlx::Error> {
+        sqlx::query_as::<_, Self>("SELECT * FROM \"user\" WHERE id = $1")
+            .bind(id)
+            .fetch_optional(pool)
+            .await
+    }
+
+    pub async fn find_by_event_and_name(
+        pool: &PgPool,
+        event_id: Uuid,
+        display_name: &str,
+    ) -> Result<Vec<Self>, sqlx::Error> {
+        sqlx::query_as::<_, Self>(
+            "SELECT * FROM \"user\" WHERE event_id = $1 AND display_name = $2",
+        )
+        .bind(event_id)
+        .bind(display_name)
+        .fetch_all(pool)
+        .await
+    }
+
+    pub async fn increment_failed_pin(pool: &PgPool, id: Uuid) -> Result<i16, sqlx::Error> {
+        let row: (i16,) = sqlx::query_as(
+            "UPDATE \"user\"
+             SET failed_pin_attempts = failed_pin_attempts + 1
+             WHERE id = $1
+             RETURNING failed_pin_attempts",
+        )
+        .bind(id)
+        .fetch_one(pool)
+        .await?;
+        Ok(row.0)
+    }
+
+    pub async fn lock_pin(pool: &PgPool, id: Uuid, until: DateTime<Utc>) -> Result<(), sqlx::Error> {
+        sqlx::query(
+            "UPDATE \"user\" SET pin_locked_until = $2 WHERE id = $1",
+        )
+        .bind(id)
+        .bind(until)
+        .execute(pool)
+        .await?;
+        Ok(())
+    }
+
+    pub async fn reset_pin_attempts(pool: &PgPool, id: Uuid) -> Result<(), sqlx::Error> {
+        sqlx::query(
+            "UPDATE \"user\" SET failed_pin_attempts = 0, pin_locked_until = NULL WHERE id = $1",
+        )
+        .bind(id)
+        .execute(pool)
+        .await?;
+        Ok(())
+    }
+}

backend/src/state.rs

@@ -0,0 +1,28 @@
+use sqlx::PgPool;
+use tokio::sync::broadcast;
+
+use crate::config::AppConfig;
+
+#[derive(Clone, Debug)]
+pub struct SseEvent {
+    pub event_type: String,
+    pub data: String,
+}
+
+#[derive(Clone)]
+pub struct AppState {
+    pub pool: PgPool,
+    pub config: AppConfig,
+    pub sse_tx: broadcast::Sender<SseEvent>,
+}
+
+impl AppState {
+    pub fn new(pool: PgPool, config: AppConfig) -> Self {
+        let (sse_tx, _) = broadcast::channel(256);
+        Self {
+            pool,
+            config,
+            sse_tx,
+        }
+    }
+}

frontend/src/lib/api.ts

@@ -0,0 +1,57 @@
+import { getToken, clearAuth } from './auth';
+
+const BASE = '/api/v1';
+
+export class ApiError extends Error {
+	status: number;
+	code: string;
+
+	constructor(status: number, code: string, message: string) {
+		super(message);
+		this.status = status;
+		this.code = code;
+	}
+}
+
+async function request<T>(
+	method: string,
+	path: string,
+	body?: unknown
+): Promise<T> {
+	const headers: Record<string, string> = {};
+	const token = getToken();
+	if (token) {
+		headers['Authorization'] = `Bearer ${token}`;
+	}
+	if (body !== undefined) {
+		headers['Content-Type'] = 'application/json';
+	}
+
+	const res = await fetch(`${BASE}${path}`, {
+		method,
+		headers,
+		body: body !== undefined ? JSON.stringify(body) : undefined
+	});
+
+	if (res.status === 204) {
+		return undefined as T;
+	}
+
+	const data = await res.json();
+
+	if (!res.ok) {
+		if (res.status === 401) {
+			clearAuth();
+		}
+		throw new ApiError(res.status, data.error ?? 'unknown', data.message ?? 'Fehler');
+	}
+
+	return data as T;
+}
+
+export const api = {
+	get: <T>(path: string) => request<T>('GET', path),
+	post: <T>(path: string, body?: unknown) => request<T>('POST', path, body),
+	patch: <T>(path: string, body?: unknown) => request<T>('PATCH', path, body),
+	delete: <T>(path: string) => request<T>('DELETE', path)
+};

frontend/src/lib/auth.ts

@@ -0,0 +1,44 @@
+import { writable } from 'svelte/store';
+import { browser } from '$app/environment';
+
+const TOKEN_KEY = 'eventsnap_jwt';
+const PIN_KEY = 'eventsnap_pin';
+const USER_ID_KEY = 'eventsnap_user_id';
+
+export const isAuthenticated = writable(false);
+
+export function getToken(): string | null {
+	if (!browser) return null;
+	return localStorage.getItem(TOKEN_KEY);
+}
+
+export function getPin(): string | null {
+	if (!browser) return null;
+	return localStorage.getItem(PIN_KEY);
+}
+
+export function getUserId(): string | null {
+	if (!browser) return null;
+	return localStorage.getItem(USER_ID_KEY);
+}
+
+export function setAuth(jwt: string, pin: string | null, userId: string): void {
+	if (!browser) return;
+	localStorage.setItem(TOKEN_KEY, jwt);
+	if (pin) localStorage.setItem(PIN_KEY, pin);
+	localStorage.setItem(USER_ID_KEY, userId);
+	isAuthenticated.set(true);
+}
+
+export function clearAuth(): void {
+	if (!browser) return;
+	localStorage.removeItem(TOKEN_KEY);
+	localStorage.removeItem(USER_ID_KEY);
+	// PIN is intentionally kept so the user can recover
+	isAuthenticated.set(false);
+}
+
+export function initAuth(): void {
+	if (!browser) return;
+	isAuthenticated.set(!!getToken());
+}

frontend/src/routes/+layout.svelte

@@ -1,8 +1,14 @@
 <script lang="ts">
 	import favicon from '$lib/assets/favicon.svg';
 	import '../app.css';
+	import { initAuth } from '$lib/auth';
+	import { onMount } from 'svelte';
 
 	let { children } = $props();
+
+	onMount(() => {
+		initAuth();
+	});
 </script>
 
 <svelte:head>

frontend/src/routes/+page.svelte

@@ -1,2 +1,14 @@
-<h1>Welcome to SvelteKit</h1>
-<p>Visit <a href="https://svelte.dev/docs/kit">svelte.dev/docs/kit</a> to read the documentation</p>
+<script lang="ts">
+	import { goto } from '$app/navigation';
+	import { getToken } from '$lib/auth';
+	import { browser } from '$app/environment';
+	import { onMount } from 'svelte';
+
+	onMount(() => {
+		if (getToken()) {
+			goto('/feed');
+		} else {
+			goto('/join');
+		}
+	});
+</script>

frontend/src/routes/feed/+page.svelte

@@ -0,0 +1,37 @@
+<script lang="ts">
+	import { goto } from '$app/navigation';
+	import { getToken, clearAuth } from '$lib/auth';
+	import { api } from '$lib/api';
+	import { onMount } from 'svelte';
+
+	onMount(() => {
+		if (!getToken()) {
+			goto('/join');
+		}
+	});
+
+	async function handleLogout() {
+		try {
+			await api.delete('/session');
+		} catch {
+			// Ignore errors — clear local state regardless
+		}
+		clearAuth();
+		goto('/join');
+	}
+</script>
+
+<div class="min-h-screen bg-gray-50 p-4">
+	<div class="mx-auto max-w-2xl">
+		<div class="mb-6 flex items-center justify-between">
+			<h1 class="text-xl font-bold text-gray-900">Galerie</h1>
+			<button
+				onclick={handleLogout}
+				class="rounded-md bg-gray-200 px-3 py-1 text-sm text-gray-700 hover:bg-gray-300"
+			>
+				Abmelden
+			</button>
+		</div>
+		<p class="text-gray-600">Die Galerie wird bald hier angezeigt.</p>
+	</div>
+</div>

frontend/src/routes/join/+page.svelte

@@ -0,0 +1,110 @@
+<script lang="ts">
+	import { goto } from '$app/navigation';
+	import { api, ApiError } from '$lib/api';
+	import { setAuth } from '$lib/auth';
+
+	let displayName = $state('');
+	let error = $state('');
+	let loading = $state(false);
+	let showPinModal = $state(false);
+	let pin = $state('');
+	let copied = $state(false);
+
+	async function handleJoin() {
+		if (!displayName.trim()) return;
+		loading = true;
+		error = '';
+		try {
+			const res = await api.post<{
+				jwt: string;
+				pin: string;
+				user_id: string;
+				is_new: boolean;
+			}>('/join', { display_name: displayName.trim() });
+
+			setAuth(res.jwt, res.pin, res.user_id);
+			pin = res.pin;
+			showPinModal = true;
+		} catch (e) {
+			if (e instanceof ApiError) {
+				error = e.message;
+			} else {
+				error = 'Ein Fehler ist aufgetreten.';
+			}
+		} finally {
+			loading = false;
+		}
+	}
+
+	function copyPin() {
+		navigator.clipboard.writeText(pin);
+		copied = true;
+		setTimeout(() => (copied = false), 2000);
+	}
+
+	function goToFeed() {
+		goto('/feed');
+	}
+</script>
+
+<div class="flex min-h-screen items-center justify-center bg-gray-50 px-4">
+	<div class="w-full max-w-sm">
+		<h1 class="mb-2 text-center text-2xl font-bold text-gray-900">Willkommen!</h1>
+		<p class="mb-6 text-center text-gray-600">Gib deinen Namen ein, um dem Event beizutreten.</p>
+
+		<form onsubmit={(e) => { e.preventDefault(); handleJoin(); }}>
+			<input
+				type="text"
+				bind:value={displayName}
+				placeholder="Dein Name"
+				maxlength={50}
+				class="mb-3 w-full rounded-lg border border-gray-300 px-4 py-3 text-lg focus:border-blue-500 focus:outline-none focus:ring-2 focus:ring-blue-200"
+			/>
+
+			{#if error}
+				<p class="mb-3 text-sm text-red-600">{error}</p>
+			{/if}
+
+			<button
+				type="submit"
+				disabled={loading || !displayName.trim()}
+				class="w-full rounded-lg bg-blue-600 px-4 py-3 text-lg font-medium text-white transition hover:bg-blue-700 disabled:opacity-50"
+			>
+				{loading ? 'Wird geladen...' : 'Beitreten'}
+			</button>
+		</form>
+
+		<p class="mt-4 text-center text-sm text-gray-500">
+			Schon dabei?
+			<a href="/recover" class="text-blue-600 hover:underline">Mit PIN wiederherstellen</a>
+		</p>
+	</div>
+</div>
+
+{#if showPinModal}
+	<div class="fixed inset-0 z-50 flex items-center justify-center bg-black/50 px-4">
+		<div class="w-full max-w-sm rounded-xl bg-white p-6 shadow-lg">
+			<h2 class="mb-2 text-xl font-bold text-gray-900">Dein Wiederherstellungs-PIN</h2>
+			<p class="mb-4 text-sm text-gray-600">
+				Merke dir diesen PIN! Du brauchst ihn, um dein Konto auf einem anderen Gerät wiederherzustellen.
+			</p>
+
+			<div class="mb-4 flex items-center justify-center gap-3 rounded-lg bg-gray-100 p-4">
+				<span class="text-4xl font-mono font-bold tracking-widest text-gray-900">{pin}</span>
+				<button
+					onclick={copyPin}
+					class="rounded-md bg-gray-200 px-3 py-1 text-sm font-medium text-gray-700 hover:bg-gray-300"
+				>
+					{copied ? 'Kopiert!' : 'Kopieren'}
+				</button>
+			</div>
+
+			<button
+				onclick={goToFeed}
+				class="w-full rounded-lg bg-blue-600 px-4 py-3 font-medium text-white transition hover:bg-blue-700"
+			>
+				Weiter zur Galerie
+			</button>
+		</div>
+	</div>
+{/if}

frontend/src/routes/recover/+page.svelte

@@ -0,0 +1,83 @@
+<script lang="ts">
+	import { goto } from '$app/navigation';
+	import { api, ApiError } from '$lib/api';
+	import { setAuth, getPin } from '$lib/auth';
+	import { browser } from '$app/environment';
+
+	let displayName = $state('');
+	let pin = $state('');
+	let error = $state('');
+	let loading = $state(false);
+
+	// Pre-fill PIN from localStorage if available
+	if (browser) {
+		const savedPin = getPin();
+		if (savedPin) pin = savedPin;
+	}
+
+	async function handleRecover() {
+		if (!displayName.trim() || !pin.trim()) return;
+		loading = true;
+		error = '';
+		try {
+			const res = await api.post<{
+				jwt: string;
+				user_id: string;
+			}>('/recover', { display_name: displayName.trim(), pin: pin.trim() });
+
+			setAuth(res.jwt, pin.trim(), res.user_id);
+			goto('/feed');
+		} catch (e) {
+			if (e instanceof ApiError) {
+				error = e.message;
+			} else {
+				error = 'Ein Fehler ist aufgetreten.';
+			}
+		} finally {
+			loading = false;
+		}
+	}
+</script>
+
+<div class="flex min-h-screen items-center justify-center bg-gray-50 px-4">
+	<div class="w-full max-w-sm">
+		<h1 class="mb-2 text-center text-2xl font-bold text-gray-900">Konto wiederherstellen</h1>
+		<p class="mb-6 text-center text-gray-600">Gib deinen Namen und deinen PIN ein.</p>
+
+		<form onsubmit={(e) => { e.preventDefault(); handleRecover(); }}>
+			<input
+				type="text"
+				bind:value={displayName}
+				placeholder="Dein Name"
+				maxlength={50}
+				class="mb-3 w-full rounded-lg border border-gray-300 px-4 py-3 text-lg focus:border-blue-500 focus:outline-none focus:ring-2 focus:ring-blue-200"
+			/>
+			<input
+				type="text"
+				bind:value={pin}
+				placeholder="4-stelliger PIN"
+				maxlength={4}
+				inputmode="numeric"
+				pattern="[0-9]*"
+				class="mb-3 w-full rounded-lg border border-gray-300 px-4 py-3 text-center text-2xl font-mono tracking-widest focus:border-blue-500 focus:outline-none focus:ring-2 focus:ring-blue-200"
+			/>
+
+			{#if error}
+				<p class="mb-3 text-sm text-red-600">{error}</p>
+			{/if}
+
+			<button
+				type="submit"
+				disabled={loading || !displayName.trim() || pin.length < 4}
+				class="w-full rounded-lg bg-blue-600 px-4 py-3 text-lg font-medium text-white transition hover:bg-blue-700 disabled:opacity-50"
+			>
+				{loading ? 'Wird geladen...' : 'Wiederherstellen'}
+			</button>
+		</form>
+
+		<p class="mt-4 text-center text-sm text-gray-500">
+			Noch kein Konto?
+			<a href="/join" class="text-blue-600 hover:underline">Neu beitreten</a>
+		</p>
+	</div>
+</div>