Three fixes for multi-session terminal bugs:
1. Race-condition double creation: The auto-create effect fired twice because
loadSessions returned 0 while an earlier createSession was still in flight.
Added hasAutoCreated guard ref to ensure only one auto-create happens.
2. Page reload spawns new sessions: After server restart, list_terminal_sessions
filtered out DB-only sessions (no in-memory counterpart), so the frontend
thought no sessions existed and auto-created new ones. Reverted the filter
so DB rows are always returned. The WebSocket handler now restores the
in-memory session from the DB row on demand when connecting.
3. No input after connection: The backend _read_loop would break on any send
error, causing asyncio.wait to cancel the _write_loop. Made _read_loop
retry up to 3 times before giving up, preventing transient send errors
from killing input handling.
Quality gates: pytest (15/15 passed), tsc clean
alex
b6e71e32f5