Remove the vendored RethinkDb driver and its Linq provider, the Rethink
backing store, the already-stubbed RethinkConnection, the Rethink test
window, and the Rethink-only Remotion.Linq and Logging.Abstractions DLLs.
The database editor now works only on GameData/AetherDB.msgpack, with a
Save button replacing the dead Connect UI and broken JSON export.
RethinkTable becomes DatabaseCategory, which only groups editor entries.
Economy.Server still references Rethink; it was already unbuildable and
is handled separately.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Copied Main Menu to gameplay scene
Added Pause functionality (ESC key)
Save & Restore discovered zones
Applied vertical offset to asteroids (no more intersections!)
Nebula shader optimized to improve early exit
Nebula shader outputs light scattering to second render target
Modified depth of field shader to use nebula light scattering
