fix(aiosqlite): improve pool shutdown and thread handling

[cofin]

Summary

• set daemon mode on aiosqlite worker threads before awaiting aiosqlite.connect() for both legacy and modern aiosqlite connection proxy shapes
• add force-stop fallback via stop() when graceful close times out (retire path and pool shutdown path)
• add unit tests covering daemon setup and close-timeout force-stop fallback for aiosqlite pools