feat: add DB-first map persistence

[suixincc]

Map edit persistence with DB-first hydration

Resolves #3.

What it does

• Adds a game_maps canonical JSONB row per map, with checksum/version metadata.
• Extends game_data_revisions with the maps kind.
• Adds an idempotent importer for all 294 mapas_source maps:
  pnpm --dir api import-game-maps.
• The importer fills missing map ids without overwriting maps that were edited after import.
• Adds internal map read/change endpoints and an admin canonical map update endpoint.
• Every map insert/edit records a game_data_revisions row with the same checksum.
• Server startup hydrates DB-published canonical maps over file maps, then applies the existing sparse tile/entity overrides.
• Unimported maps continue to load from mapas_source, so partial migrations are safe.

Testing

• API tsc --noEmit
• Server tsc --noEmit
• Server eslint
• Server focused tests: 5 passed

The new API integration tests cover:

• all 294 maps are available after import;
• a second import does not add revisions;
• edited maps are read from DB with a checksum;
• each edit creates one revision;
• unchanged edits do not create another revision.

[gitar-bot]

Gitar is working

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