b55300ff6f
- Add TerminalSessionModel DB table with instance_id FK, name, status, created_at, last_activity_at, closed_at columns - Add Alembic migration for terminal_sessions table - Refactor TerminalManager to use composite key (instance_id, session_id) supporting up to 5 concurrent sessions per instance - Add create_session, get_session, get_sessions_for_instance, close_session - Preserve get_or_create_session for backward compatibility (default session) - Fix attach_websocket to only close sockets within same session - Add name (auto-generated 'Session N') and status tracking to TerminalSession - Add 7 unit tests for multi-session logic Quality gates: pytest (7 new passed, 174 total passed, 51 pre-existing failures)