chore: initial project scaffold

Set up Mangalord with a Rust/axum backend, SvelteKit frontend, Postgres,
and Docker Compose deployment. Establishes the architecture and TDD
patterns the project will extend:

- Hexagonal-ish backend layering (domain / repo / storage / api) with
  a pluggable Storage trait (LocalStorage today, S3 as a future impl).
- Initial migration: users, mangas, chapters, bookmarks.
- Vertical slice for mangas (list, search, create, get) with
  #[sqlx::test] integration coverage and storage unit tests.
- SvelteKit frontend using Svelte 5 runes, typed API client, Vitest
  unit tests and Playwright e2e with route mocking.
- CLAUDE.md documenting layering, TDD/git/SemVer workflow rules, and
  extension points (tags, fulltext search, OCR, S3, auth).
- Project-scoped .claude/settings.json with permission allowlist for
  the toolchain (git, cargo, npm/vite, docker, psql, gh, doc fetches).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

backend/migrations/0001_init.sql

@@ -0,0 +1,49 @@
+-- Initial schema for Mangalord.
+-- Designed for future extensions: tags, lists, fulltext/fuzzy search,
+-- OCR-derived metadata. New concepts get new tables joined here; do
+-- not jam them onto existing rows.
+
+CREATE EXTENSION IF NOT EXISTS "pgcrypto";
+
+CREATE TABLE users (
+    id          uuid PRIMARY KEY DEFAULT gen_random_uuid(),
+    username    text NOT NULL UNIQUE,
+    created_at  timestamptz NOT NULL DEFAULT now()
+);
+
+CREATE TABLE mangas (
+    id                uuid PRIMARY KEY DEFAULT gen_random_uuid(),
+    title             text NOT NULL,
+    author            text,
+    description       text,
+    cover_image_path  text,
+    created_at        timestamptz NOT NULL DEFAULT now(),
+    updated_at        timestamptz NOT NULL DEFAULT now()
+);
+
+CREATE INDEX mangas_created_at_idx ON mangas (created_at DESC);
+CREATE INDEX mangas_title_lower_idx ON mangas (lower(title));
+
+CREATE TABLE chapters (
+    id           uuid PRIMARY KEY DEFAULT gen_random_uuid(),
+    manga_id     uuid NOT NULL REFERENCES mangas(id) ON DELETE CASCADE,
+    number       integer NOT NULL,
+    title        text,
+    page_count   integer NOT NULL DEFAULT 0,
+    created_at   timestamptz NOT NULL DEFAULT now(),
+    UNIQUE (manga_id, number)
+);
+
+CREATE INDEX chapters_manga_idx ON chapters (manga_id, number);
+
+CREATE TABLE bookmarks (
+    id           uuid PRIMARY KEY DEFAULT gen_random_uuid(),
+    user_id      uuid NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    manga_id     uuid NOT NULL REFERENCES mangas(id) ON DELETE CASCADE,
+    chapter_id   uuid REFERENCES chapters(id) ON DELETE SET NULL,
+    page         integer,
+    created_at   timestamptz NOT NULL DEFAULT now(),
+    UNIQUE (user_id, manga_id, chapter_id)
+);
+
+CREATE INDEX bookmarks_user_idx ON bookmarks (user_id, created_at DESC);