fix(telegram): harden DM topic binding — persist through switch_session, rebind on /new

Follow-up on @EmelyanenkoK's feat: add Telegram DM topic-mode sessions.

Three issues:

1. Split-brain session state. After get_or_create_session() returned a
   SessionEntry for a topic lane, the handler was mutating
   .session_id in place to the binding's target, but never persisting
   the switch through SessionStore. The sessions.json session_key →
   session_id map kept pointing at the lane's natural id; any reader
   that reloaded from disk saw the wrong id. Fixed by routing through
   SessionStore.switch_session(), which _save()s the mapping and ends
   the old session in SQLite like /resume does.

2. /new inside a topic was a one-message no-op. Reset created a new
   session but left the telegram_dm_topic_bindings row pointing at the
   old session_id, so the next message's binding lookup switched right
   back. Now _handle_reset_command rebinds the topic to the new
   session_id after reset.

3. is_telegram_session_linked_to_topic and
   list_unlinked_telegram_sessions_for_user both called
   apply_telegram_topic_migration() on read, contradicting the PR's
   own invariant that migration only runs on explicit /topic opt-in.
   They now tolerate missing topic tables and return empty/False.

Also: _telegram_topic_mode_enabled() now only treats True as enabled
(not any truthy return), so test fixtures with MagicMock session_db
don't accidentally flip every DM into lobby mode — this was breaking
4 pre-existing test_status_command tests.

Tests:
- New regression: /new inside a topic must update the binding row
  (test_new_inside_telegram_topic_rewrites_binding_to_new_session).
- _make_runner now stubs switch_session so existing restore tests
  still exercise the new code path.

Validated end-to-end with real SessionDB + SessionStore:
readers on fresh DB don't create topic tables; enable creates them;
binding override persists across SessionStore restart; /new rebinds
and the new id survives a restart.

Co-authored-by: EmelyanenkoK <emelyanenko.kirill@gmail.com>

scripts/release.py

@@ -55,6 +55,7 @@ AUTHOR_MAP = {
     "14046872+tmimmanuel@users.noreply.github.com": "tmimmanuel",
     "657290301@qq.com": "IMHaoyan",
     "revar@users.noreply.github.com": "revaraver",
+    "emelyanenko.kirill@gmail.com": "EmelyanenkoK",
     # Matrix parity salvage batch (April 2026)
     "sr@samirusani": "samrusani",
     "angelclaw@AngelMacBook.local": "angel12",