feat: Support SQLite GTFS Hot-Swap on Daily Static Updates

[Ahmedhossamdev]

The daily GTFS update flow refreshes in-memory static data only.
The persistent SQLite database (gtfs.db) is not rebuilt, causing SQL-backed endpoints to serve stale data.

TODOs

• Build New SQLite Database
  After downloading the new GTFS feed in updateStaticGTFS, build a fresh SQLite database to a temporary file (e.g. gtfs_next.db) with all tables and indexes.

• Initialize New GtfsDB Client
  Open a new GtfsDB client using the newly built database and verify it is readable before activation.

• Hot-Swap Active GtfsDB
  Atomically replace the active GtfsDB client in Manager so new requests use the updated database without downtime.

• Sync In-Memory Static Data
  Reload or realign in-memory static data structures to ensure consistency with the newly swapped SQLite database.

• Clean Up Old Database
  Gracefully close the old database connection and remove the previous SQLite file after the swap succeeds.

Acceptance Criteria

• SQLite-backed endpoints serve fresh GTFS data after the daily update
• No downtime or inconsistent reads during the database swap
• In-memory and persistent GTFS data remain in sync

[mann-patwa]

Hey @Ahmedhossamdev could you assign this to me?

[Ahmedhossamdev]

@mann-patwa Done