Integrate the Blender character, gear and prop library

NpcAvatar
- select one of 8 library character variants by role/seed (with npc_base and the
  procedural rig as fallbacks), keep Rig/Head and the existing bone animation
- tint only skin/cloth/pants/accessory/hair; fixed detail materials keep their
  colour, npc_vest keeps its hi-vis vest, firefighter/guard use dark uniform tints
- attach caps, hoods, helmets, backpacks, SCBA tanks, lanyards and hand items at
  the documented head/back/chest/hand points (primitive fallbacks retained)

WorldBuilder
- prefer assets/models/blender/props/ for the six replacements and the new
  street dressing (street lamp/tree, palms, planters, A-frame, cone, barrier,
  stanchion, podium, handrail, wall lantern, double door, marquee, sedan)
- fit the same colliders/navigation obstacles and keep the placement validator;
  collect library emissives (bulbs, marquee face, wall lanterns, door LED, sedan
  lights) for set_night_mode()
- add a library triangle counter + 60k budget check (current ~27,986); toggle
  prop gallery to the library models; fix the marquee label placement

Tests/smoke
- character selection/gear attach/fixed-material tint tests; library prop load,
  emissive and triangle-budget tests; smoke_props routes a guest around a
  stanchion in open sidewalk (the old bench route is now crowded by trees)
- headless 222/222, Python 68/68, all smokes pass, compare 11 good / 0 bad

Docs: TODO Phase 3.5 moved to DONE, README/architecture/blender-assets/plan
describe the integrated runtime, MEMORY records the integration rules.

docs/architecture.md

@@ -80,7 +80,7 @@ The player interacts with NPCs, venue entrances, access artifacts, equipment, st
 - `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).
-- `tools/blender_assets.py` builds, renders and audits the staged Blender asset library (`assets/models/blender/{npc,npc_gear,props}/` + `manifest.json`): NPC character variants that are drop-in for `npc_base`, attach-point gear, and street/venue props. Not loaded at runtime yet (see `docs/blender-assets.md`).
+- `tools/blender_assets.py` builds, renders and audits the Blender asset library (`assets/models/blender/{npc,npc_gear,props}/` + `manifest.json`): NPC character variants that are drop-in for `npc_base`, attach-point gear, and street/venue props. `NpcAvatar` selects variants/gear by role/seed and `WorldBuilder` loads the prop replacements and new street dressing, with procedural fallbacks (see `docs/blender-assets.md`).
 - `tools/asset_pipeline.py` generates and audits role-aware textures; `tools/screen_designs.py` generates screen references and judges captures.
 
 Confirmed game assets live in `assets/textures/ai/game_ready/` (audited surface, UI, and card textures), `assets/models/generated/` (prop and NPC `.glb` models plus their texture atlases), and `assets/textures/npc/` (NPC material maps and `palette.json`). Development-only outputs — AI concept sheets, Blender sources, raw AI fabrics — are gitignored and regenerated by the tools.