fix(server): enable checkpoint_fullfsync for SQLite WAL checkpoints on macOS

[macodev00]

What Changed

After enabling WAL on the server SQLite connection, setup now runs PRAGMA checkpoint_fullfsync = ON. WAL checkpoints on macOS then request F_FULLFSYNC. Ordinary commits keep using plain fsync(): PRAGMA fullfsync stays off.

The same per-connection pragma is set on the t3-sqlite-state and migrate-dev-db writer connections that bypass Sqlite.ts and can checkpoint state.sqlite, including the migration liveness probe that runs wal_checkpoint(TRUNCATE).

Tests read the pragmas back on the persistence layer and the state script: checkpoint_fullfsync = 1, fullfsync = 0.

Why

Issue pingdotgg#13544 is an accepted bug. A hard shutdown on macOS can corrupt state.sqlite because WAL checkpoints sync with fsync(), which does not flush the drive cache. Julius prescribed this fix in triage: after WAL, run PRAGMA checkpoint_fullfsync = ON, and leave ordinary fullfsync off.

This is not a broad product persistence default change. It only makes checkpoint sync durable on the connections that already checkpoint state.sqlite. Per-commit sync is unchanged because fullfsync stays off. Where F_FULLFSYNC is absent, the pragma is a no-op.

Fixes pingdotgg#13544

UI Changes

None.

Checklist

• This PR is small and focused
• I explained what changed and why
• I included before/after screenshots for any UI changes
• I included a video for animation/interaction changes