Stage the Blender character/gear/prop library

Commit the finished generator output from the parallel Blender pass:
8 skinned NPC variants, 18 gear pieces, and 20 props under
assets/models/blender/, editable sources (gdignored), manifest, review sheets,
and the integration notes in docs/blender-assets.md.

- audit: all 46 assets clean (characters 3,788-4,640 tris, under 6000/4000)
- tests: Python manifest/audit contract and Godot import/bone/slot/ground checks
- docs: README library section, architecture/plan references, TODO Phase 3.5
  status, MEMORY integration rules
- .gitignore: per-asset preview PNGs, extracted GLB textures, blend1 backups

Nothing in the game loads the library yet; integration follows." && git log --oneline -1

PLAN.md

@@ -413,7 +413,7 @@ existing AI tools remain the source of art direction for fabric textures, palett
 screen-design compare/judge gate.
 
 The library targets 8 character variants (casual, jacket, coat, vest, dress, hoodie, firefighter,
-guard), 18 gear pieces, and 22 props — including replacements for the current generated street
+guard), 18 gear pieces, and 20 props — including replacements for the current generated street
 furniture, lamps, trees, doors, marquee, and a venue car. Integration must preserve the
 `Rig/Head` focus anchor, seed-driven outfit determinism, collider/navigation footprints, and the
 frame budget measured by `smoke_npc_budget.gd`. See