- Empty string titles normalized to None (prevents uncaught IntegrityError
when two sessions both get empty-string titles via the unique index)
- Escape SQL LIKE wildcards (%, _) in resolve_session_by_title and
get_next_title_in_lineage to prevent false matches on titles like
'test_project' matching 'testXproject #2'
- Optimize list_sessions_rich from N+2 queries to a single query with
correlated subqueries (preview + last_active computed in SQL)
- Add /title slash command to gateway (Telegram, Discord, Slack, WhatsApp)
with set and show modes, uniqueness conflict handling
- Add /title to gateway /help text and _known_commands
- 12 new tests: empty string normalization, multi-empty-title safety,
SQL wildcard edge cases, gateway /title set/show/conflict/cross-platform