feat(p3): add discovery, telegram notifications, and one-click favorites

Implement WBI video search with legacy fallback, classification scoring, candidate pool, permanent seen-aid dedupe, blacklist filtering, and batched Telegram notifications. Add write client for fav deal/sort, target-folder selection, insertion position calculation, read-back verification, fav_action locking, retry on failure, ignore and blacklist actions. Wire discovery, candidate cleanup, Telegram long polling, and new discover/candidates CLI commands into the scheduler. Add migration v3 for candidate duration and index stats.

tests/test_database.py

@@ -24,7 +24,7 @@ def test_write_read_transaction():
     with tempfile.TemporaryDirectory() as tmp:
         db = make_db(tmp)
         try:
-            assert db.schema_version == 2
+            assert db.schema_version == 3
             db.write(lambda c: c.execute("INSERT INTO kv(k, v) VALUES ('a', '1')"))
             assert db.read(lambda c: c.execute("SELECT v FROM kv WHERE k='a'").fetchone()[0]) == "1"
 
@@ -94,8 +94,8 @@ def test_close_and_reinitialize():
 
         db2 = make_db(tmp)
         try:
-            assert db2.schema_version == 2
-            assert db2.read(lambda c: c.execute("SELECT MAX(version) FROM schema_version").fetchone()[0]) == 2
+            assert db2.schema_version == 3
+            assert db2.read(lambda c: c.execute("SELECT MAX(version) FROM schema_version").fetchone()[0]) == 3
         finally:
             db2.close()
 
@@ -123,7 +123,7 @@ def test_migration_backup_on_existing_db():
         db = Database(path, backup_dir=Path(tmp) / "backup")
         try:
             applied = db.initialize()
-            assert applied == [1, 2]
+            assert applied == [1, 2, 3]
             assert len(list((Path(tmp) / "backup").glob("app-pre-v0-*.db"))) == 1
         finally:
             db.close()