feat(channel): page details chaine multi-providers avec onglets et infinite scroll

- Strategy Pattern front: ChannelProviderInterface + 6 providers (yt/dm/tw/pt/od/ru) + factory (ids longs/courts)
- ChannelContentService: cache par onglet/tri/recherche (TTL 5min), pagination nextPage
- ChannelPage: header (banniere/avatar/subs/description ...plus), tabs dynamiques par capabilities, grilles videos/shorts 9:16/playlists/live, recherche debounced, tri recent/populaire, infinite scroll IntersectionObserver, skeletons/empty/error
- Backend: GET /api/channels/:provider/:id/content (videos/shorts/playlists/live) natif par provider

db/migrations/20250923_add_subscriptions_tables.sql

@@ -0,0 +1,27 @@
+BEGIN TRANSACTION;
+
+CREATE TABLE IF NOT EXISTS channels (
+  id INTEGER PRIMARY KEY AUTOINCREMENT,
+  provider TEXT NOT NULL,
+  external_id TEXT NOT NULL,
+  title TEXT,
+  handle TEXT,
+  avatar_url TEXT,
+  url TEXT,
+  subs_count INTEGER,
+  verified INTEGER DEFAULT 0,
+  last_refreshed_at INTEGER,
+  UNIQUE(provider, external_id)
+);
+
+CREATE TABLE IF NOT EXISTS subscriptions (
+  id INTEGER PRIMARY KEY AUTOINCREMENT,
+  user_id INTEGER NOT NULL,
+  channel_id INTEGER NOT NULL REFERENCES channels(id) ON DELETE CASCADE,
+  created_at INTEGER NOT NULL,
+  UNIQUE(user_id, channel_id)
+);
+
+CREATE INDEX IF NOT EXISTS idx_subs_user ON subscriptions(user_id);
+
+COMMIT;

db/migrations/20250924_add_default_providers.sql

@@ -0,0 +1,2 @@
+-- Add multi-provider default selection (JSON array string, e.g. '["yt","dm"]').
+ALTER TABLE user_preferences ADD COLUMN default_providers TEXT;

db/migrations/20250924_add_download_jobs.sql

@@ -0,0 +1,28 @@
+-- Persistent download queue: jobs survive API restarts, per-user scoping
+BEGIN TRANSACTION;
+
+CREATE TABLE IF NOT EXISTS download_jobs (
+  id TEXT PRIMARY KEY,
+  user_id TEXT NOT NULL,
+  provider TEXT NOT NULL,
+  video_id TEXT NOT NULL,
+  title TEXT,
+  state TEXT NOT NULL DEFAULT 'queued',        -- queued|running|merging|completed|failed|interrupted
+  progress REAL NOT NULL DEFAULT 0,
+  format_id TEXT,
+  audio_only INTEGER NOT NULL DEFAULT 0,
+  url TEXT,
+  file_name TEXT,
+  file_ext TEXT,
+  file_size INTEGER,
+  file_path TEXT,
+  error TEXT,
+  created_at INTEGER NOT NULL,
+  updated_at INTEGER NOT NULL,
+  completed_at INTEGER
+);
+
+CREATE INDEX IF NOT EXISTS idx_download_jobs_user ON download_jobs(user_id, created_at DESC);
+CREATE INDEX IF NOT EXISTS idx_download_jobs_state ON download_jobs(state);
+
+COMMIT;

db/migrations/20250924_add_telemetry_events.sql

@@ -0,0 +1,11 @@
+-- Minimal telemetry for the unified search UX (Step 13).
+-- Stores anonymous, non-identifying product events.
+CREATE TABLE IF NOT EXISTS telemetry_events (
+  id TEXT PRIMARY KEY,
+  user_id TEXT,
+  event TEXT NOT NULL,
+  meta_json TEXT,
+  created_at TEXT NOT NULL
+);
+CREATE INDEX IF NOT EXISTS idx_telemetry_event_time ON telemetry_events(event, created_at DESC);
+CREATE INDEX IF NOT EXISTS idx_telemetry_user_time ON telemetry_events(user_id, created_at DESC);

db/schema.sql

@@ -19,6 +19,7 @@ CREATE TABLE IF NOT EXISTS user_preferences (
   user_id TEXT PRIMARY KEY REFERENCES users(id) ON DELETE CASCADE,
   language TEXT DEFAULT 'en',
   default_provider TEXT,
+  default_providers TEXT,
   theme TEXT DEFAULT 'system',
   video_quality TEXT DEFAULT 'auto',
   region TEXT,
@@ -83,32 +84,30 @@ CREATE TABLE IF NOT EXISTS watch_history (
 CREATE UNIQUE INDEX IF NOT EXISTS uq_watch_history_user_video ON watch_history(user_id, provider, video_id);
 CREATE INDEX IF NOT EXISTS idx_watch_history_user_time ON watch_history(user_id, watched_at DESC);
 
--- Subscriptions & categories -----------------------------------------------
-CREATE TABLE IF NOT EXISTS categories (
-  id TEXT PRIMARY KEY,
-  user_id TEXT NOT NULL REFERENCES users(id) ON DELETE CASCADE,
-  name TEXT NOT NULL,
-  created_at TEXT NOT NULL,
-  UNIQUE(user_id, name)
+-- Channels cache & subscriptions --------------------------------------------
+CREATE TABLE IF NOT EXISTS channels (
+  id INTEGER PRIMARY KEY AUTOINCREMENT,
+  provider TEXT NOT NULL,
+  external_id TEXT NOT NULL,
+  title TEXT,
+  handle TEXT,
+  avatar_url TEXT,
+  url TEXT,
+  subs_count INTEGER,
+  verified INTEGER DEFAULT 0,
+  last_refreshed_at INTEGER,
+  UNIQUE(provider, external_id)
 );
 
 CREATE TABLE IF NOT EXISTS subscriptions (
-  id TEXT PRIMARY KEY,
-  user_id TEXT NOT NULL REFERENCES users(id) ON DELETE CASCADE,
-  provider TEXT NOT NULL,
-  channel_id TEXT NOT NULL,
-  channel_name TEXT,
-  notify INTEGER NOT NULL DEFAULT 0,
-  subscribed_at TEXT NOT NULL,
-  UNIQUE(user_id, provider, channel_id)
+  id INTEGER PRIMARY KEY AUTOINCREMENT,
+  user_id INTEGER NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+  channel_id INTEGER NOT NULL REFERENCES channels(id) ON DELETE CASCADE,
+  created_at INTEGER NOT NULL,
+  UNIQUE(user_id, channel_id)
 );
 
-CREATE TABLE IF NOT EXISTS subscription_categories (
-  subscription_id TEXT NOT NULL REFERENCES subscriptions(id) ON DELETE CASCADE,
-  category_id TEXT NOT NULL REFERENCES categories(id) ON DELETE CASCADE,
-  PRIMARY KEY (subscription_id, category_id)
-);
-CREATE INDEX IF NOT EXISTS idx_subscriptions_user ON subscriptions(user_id);
+CREATE INDEX IF NOT EXISTS idx_subs_user ON subscriptions(user_id);
 
 -- Playlists -----------------------------------------------------------------
 CREATE TABLE IF NOT EXISTS playlists (