Drag down now raises the camera so the galaxy shifts down with the cursor
(content follows finger). Horizontal was already correct (drag right moves
the scene right). Matches the feel of panning a map on iOS.
- Refactor apps/game/src/main.rs into modules: state.rs, camera.rs, ui/, gameplay/
- Add gameplay/galaxy_creation.rs scaffold (stubs only, no new logic)
- Update root AGENTS.md: separate TS workspace vs Rust game commands
- Update apps/AGENTS.md: docs/game/site use two toolchains, not one
- Add apps/game/AGENTS.md: build commands, module layout, naming conventions, Plugin pattern