Bake library AO and lift environment textures

Phase 4 of the v0.6.0 graphics plan:

- tools/bake_ao.py bakes 256² AO maps for every Blender character/gear/prop
  (Cycles, existing UVs) next to each GLB; Materials.apply_ao() wires the red
  channel into character slots, gear, and props. Compatibility has no SSAO.
- Regenerated brick/concrete/asphalt at 1024² with OpenRouter, derived tangent
  normal maps via tools/make_normal_maps.py, and wired them through
  SurfaceMaterials.textured() without changing UV scales.
- Evaluated Forward+: boots on desktop Vulkan, but the renderer is project-wide
  and Web must stay GL Compatibility; v0.6.0 keeps Compatibility (decision in
  MEMORY/plan). A desktop-only override is deferred.
- Recaptured screenshots; compare 11 good / 0 bad. Fixed marquee text alignment.
- Tests: baked AO maps exist for all 46 assets; prop/character AO material
  checks; headless 222/222, Python 69/69, all smokes pass.
- Version 0.6.0; ADR-0013 accepted; README/architecture/blender-assets/plan and
  TODO/DONE updated.

docs/architecture.md

@@ -76,7 +76,7 @@ The player interacts with NPCs, venue entrances, access artifacts, equipment, st
 - `ReputationEvaluator` converts incidents and shift outcomes into performance feedback.
 - `CrowdSystem` models queues, attention, congestion, and public reaction.
 - `ShiftReview` presents decisions, consequences, and improvement opportunities.
-- `SurfaceMaterials` (`src/game/materials.gd`) holds the surface profiles, glass/emissive recipes, and the environment tune-up (tonemapping, glow, fog, grading) that the phase lighting applies.
+- `SurfaceMaterials` (`src/game/materials.gd`) holds the surface profiles, textured albedo/normal recipes, baked-AO wiring, glass/emissive recipes, and the environment tune-up (tonemapping, glow, fog, grading) that the phase lighting applies.
 - `WorldBuilder` assembles the procedural venue and instantiates the generated prop models from `assets/models/generated/` with a procedural fallback.
 - `tools/model_pipeline.py` builds and audits the street-prop `.glb` models and packs their colour atlases.
 - `tools/npc_pipeline.py` builds and audits the skinned NPC base model (`assets/models/generated/npc_base.glb`) and its per-slot material maps, with an optional AI fabric override (ADR-0013).