refactor(server): plumb Arc<Settings> through workers and routes

Config sheds its 14 Bucket-B fields (retention, whisper, ollama, llm) and
gains a sibling Arc<Settings> in AppState, loaded from settings.toml at
startup via Settings::load_or_default. Workers (transcribe, analyze,
recovery, auto_trigger) and routes (health, bulk, case_actions,
user_web) take settings as a separate parameter or State<> extractor;
Config::llm_configured moves to Settings::llm_configured.

TestConfig::build_pair() returns (Arc<Config>, Arc<Settings>); the new
create_router_with_settings / create_router_and_session_store_with_settings
helpers wire both into integration tests that exercise LLM/Whisper/Ollama.
The legacy single-Arc create_router falls back to Settings::default()
so the 17 non-LLM tests stay untouched.

Verified: cargo build clean, clippy --all-targets clean, 318 tests pass.

server/src/lib.rs

@@ -12,6 +12,7 @@ pub mod oneliner_locks;
 pub mod paths;
 pub mod retention;
 pub mod routes;
+pub mod settings;
 pub mod transcribe;
 pub mod web_session;
 
@@ -28,6 +29,7 @@ use config::Config;
 use gazetteer::Gazetteer;
 use magic_link::MagicLinkStore;
 use oneliner_locks::OnelinerLocks;
+use settings::Settings;
 use transcribe::TranscribeSender;
 use web_session::SessionStore;
 
@@ -88,6 +90,7 @@ pub struct PipelineState {
 #[derive(Clone)]
 pub struct AppState {
     pub config: Arc<Config>,
+    pub settings: Arc<Settings>,
     pub transcribe_tx: TranscribeSender,
     pub analyze_tx: AnalyzeSender,
     pub session_store: SessionStore,
@@ -107,6 +110,12 @@ impl FromRef<AppState> for Arc<Config> {
     }
 }
 
+impl FromRef<AppState> for Arc<Settings> {
+    fn from_ref(state: &AppState) -> Self {
+        state.settings.clone()
+    }
+}
+
 impl FromRef<AppState> for TranscribeSender {
     fn from_ref(state: &AppState) -> Self {
         state.transcribe_tx.clone()
@@ -199,11 +208,27 @@ pub fn create_router(config: Arc<Config>) -> Router {
 /// shared with the router (`Arc`), so any session created via `/web/login`
 /// or `/web/magic` becomes observable through it.
 pub fn create_router_and_session_store(config: Arc<Config>) -> (Router, SessionStore) {
+    create_router_and_session_store_with_settings(config, Arc::new(Settings::default()))
+}
+
+/// Variant of [`create_router`] that takes both `Config` and `Settings`.
+/// Use from tests that exercise Bucket-B paths (LLM, Whisper, Ollama URLs);
+/// otherwise the [`create_router`] convenience with default Settings is enough.
+pub fn create_router_with_settings(config: Arc<Config>, settings: Arc<Settings>) -> Router {
+    create_router_and_session_store_with_settings(config, settings).0
+}
+
+/// Variant of [`create_router_and_session_store`] that takes both `Config` and `Settings`.
+pub fn create_router_and_session_store_with_settings(
+    config: Arc<Config>,
+    settings: Arc<Settings>,
+) -> (Router, SessionStore) {
     let (transcribe_tx, _transcribe_rx) = transcribe::channel();
     let (analyze_tx, _analyze_rx) = analyze::channel();
     let session_store = web_session::new_store();
     let router = create_router_with_state(AppState {
         config,
+        settings,
         transcribe_tx,
         analyze_tx,
         session_store: session_store.clone(),