feat(cli): pic secrets --group, value read, and effective vars/config

Mirrors `pic vars` on the secrets surface: `pic secrets ls/set/rm` take an
`--app`/`--group` owner selector (exactly-one) with `--env` for group
secrets. Adds `pic secrets read --group <g> <name> [--env]` — the only
command that reveals a secret value, hitting the group-gated value
endpoint. `pic config --effective` now folds in the resolved vars section
(value + owner + scope) and an `--explain` provenance view, alongside the
existing masked-secrets cross-reference, via `GET /config/effective`.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

crates/picloud-cli/src/cmds/secrets.rs

@@ -1,31 +1,56 @@
-//! `pic secrets` subcommands: `ls`, `set`, `rm`.
+//! `pic secrets ls | set | rm | read` — manage Phase-3 group/app secrets.
 //!
-//! Set reads the secret value from stdin (the only safe channel —
-//! inline values would leak into shell history). The value is sent
-//! as a JSON string; pass `--json` to interpret stdin as raw JSON
-//! (numbers, maps, …) instead.
+//! Exactly one of `--group` / `--app` selects the owner (mirroring
+//! `pic vars`). Set reads the secret value from stdin (the only safe
+//! channel — inline values would leak into shell history). The value is
+//! sent as a JSON string; pass `--json` to interpret stdin as raw JSON
+//! (numbers, maps, …) instead. `--env` is only meaningful for group
+//! owners (app secrets are env-agnostic).
 
 use std::io::Read;
 
 use anyhow::{anyhow, Context, Result};
 
-use crate::client::Client;
+use crate::client::{Client, VarOwnerArg};
 use crate::config;
 use crate::output::{OutputMode, Table};
 
-pub async fn ls(app: &str, mode: OutputMode) -> Result<()> {
+/// Resolve the `--group`/`--app` pair into exactly one owner.
+fn owner<'a>(group: Option<&'a str>, app: Option<&'a str>) -> Result<VarOwnerArg<'a>> {
+    match (group, app) {
+        (Some(g), None) => Ok(VarOwnerArg::Group(g)),
+        (None, Some(a)) => Ok(VarOwnerArg::App(a)),
+        (Some(_), Some(_)) => Err(anyhow!("pass exactly one of --group / --app, not both")),
+        (None, None) => Err(anyhow!("pass one of --group / --app")),
+    }
+}
+
+pub async fn ls(
+    group: Option<&str>,
+    app: Option<&str>,
+    env: Option<&str>,
+    mode: OutputMode,
+) -> Result<()> {
+    let owner = owner(group, app)?;
     let creds = config::resolve()?;
     let client = Client::from_creds(&creds)?;
-    let resp = client.secrets_list(app).await?;
-    let mut table = Table::new(["name", "updated_at"]);
+    let resp = client.secrets_list(owner, env).await?;
+    let mut table = Table::new(["name", "env", "updated_at"]);
     for s in resp.secrets {
-        table.row([s.name, s.updated_at.to_rfc3339()]);
+        table.row([s.name, s.env, s.updated_at.to_rfc3339()]);
     }
     table.print(mode);
     Ok(())
 }
 
-pub async fn set(app: &str, name: &str, as_json: bool) -> Result<()> {
+pub async fn set(
+    group: Option<&str>,
+    app: Option<&str>,
+    name: &str,
+    env: Option<&str>,
+    as_json: bool,
+) -> Result<()> {
+    let owner = owner(group, app)?;
     let creds = config::resolve()?;
     let client = Client::from_creds(&creds)?;
     let mut buf = String::new();
@@ -41,15 +66,36 @@ pub async fn set(app: &str, name: &str, as_json: bool) -> Result<()> {
     } else {
         serde_json::Value::String(trimmed.to_string())
     };
-    client.secrets_set(app, name, value).await?;
+    client.secrets_set(owner, name, value, env).await?;
     println!("Set secret {name}");
     Ok(())
 }
 
-pub async fn rm(app: &str, name: &str) -> Result<()> {
+pub async fn rm(
+    group: Option<&str>,
+    app: Option<&str>,
+    name: &str,
+    env: Option<&str>,
+) -> Result<()> {
+    let owner = owner(group, app)?;
     let creds = config::resolve()?;
     let client = Client::from_creds(&creds)?;
-    client.secrets_delete(app, name).await?;
+    client.secrets_delete(owner, name, env).await?;
     println!("Deleted secret {name}");
     Ok(())
 }
+
+/// `pic secrets read --group <slug> <name>` — fetch and print a secret's
+/// PLAINTEXT value. This is the ONLY command that reveals a secret value,
+/// and it is gated server-side at the owning group (there is no app-secret
+/// equivalent). String values print raw; JSON values print pretty.
+pub async fn read(group: &str, name: &str, env: Option<&str>) -> Result<()> {
+    let creds = config::resolve()?;
+    let client = Client::from_creds(&creds)?;
+    let resp = client.group_secret_read_value(group, name, env).await?;
+    match resp.value {
+        serde_json::Value::String(s) => println!("{s}"),
+        other => println!("{}", serde_json::to_string_pretty(&other)?),
+    }
+    Ok(())
+}