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_config.py

@@ -54,6 +54,9 @@ def test_dual_accounts_and_env_override():
         assert (cfg.bilibili.write.mid, cfg.bilibili.write.csrf, cfg.bilibili.write.cookie) == (202, "env-write", "env-write-cookie")
         assert cfg.storage.database_path == Path(tmp) / "custom.db"
         assert cfg.up_blacklist_seed == (1, 2)
+        assert cfg.discover.keywords == ("咻咻满 reaction", "咻咻满 充电")
+        assert cfg.discover.pages == 2
+        assert cfg.classify["self_mid"] == 37754047
 
 
 def test_flat_and_missing_account_rejected():