Change the 3D scene

Rules: SCENE.md, TESTING.md, PRIVACY_SECURITY.md (text via textContent).

1. Organization or positions? Start in pure code, test-first (packages/web/src/app/):
   • who goes where → packages/shared/src/grouping.ts (+ grouping.test.ts)
   • which wing a provider gets, annexes, world anchors and the merged nav graph → building.ts
   • which desk an agent gets (topic → pod, subagents next to the parent, stable seats) → seating.ts
   • which room an agent goes to and when (meeting, booth, kitchen, lounge, cafe, ping-pong, arriving, leaving) → behavior.ts + reservations.ts
   • how it gets there (paths, timing, clip sequences, no snapping) → navigation.ts + choreography.ts
   • what the panel and tags say → view-models.ts (activityLabel, data-activity)
   • Positions come only from manifest anchors (docs/graphics-contract.md). If the building itself must change, that is /asset-change.
2. Visuals (packages/web/src/adapters/three/*): the scene implements the SceneView port — decisions stay in the controller and the pure modules. Load the Blender-built glbs and the character from public/assets (served under app://renderer/assets/… in production), reuse cached geometries and materials (clone per instance only for tinted materials, screens and LEDs), colors only from STATUS_COLORS, no allocations in update(), dispose on removal. Respect the quality preset passed to setQuality and the animation rules in SCENE.md (in-place clips, crossfades, Walk timeScale follows speed).
3. Verify visually with /run-office: the atrium, Main Street and each wing; agents sitting exactly at their seats, walking without foot sliding, rooms used as expected; labels not overlapping; light and dark mode; walk mode collisions. make screenshots captures the fixed camera bookmarks.
4. Perf budget: make perf (150 mock agents, FPS report; target ≥ 55 fps average at Medium). Interactively: with make dev-mock running, curl -X POST -H "authorization: Bearer $(cat ~/.agent-office/token)" 'http://127.0.0.1:4317/api/mock?n=150' and open ?stats for FPS, draw calls and triangles.
5. UI or behavior change → add/adjust a spec in packages/desktop/e2e/ (building, behavior, quality; assert on data-activity and panel text); run make build test-ui.
6. make check.

2D RPG mode: see docs/2d-architecture.md. The pure logic is in web/src/app/pixel/*, the Canvas2D drawing in web/src/adapters/pixel/*, the art in assets/pixel/src (make pixel-assets), and the floor plans come from make assets-plan. Check both modes with pixel.spec.ts and the existing 3D specs.