Rewrite NPC plans around the Quaternius base

docs/adr/0015-npc-model-variety-sourcing.md

@@ -1,8 +1,14 @@
 # ADR-0015: NPC model variety sourcing
 
-- **Status:** Accepted (planning)
+- **Status:** Superseded by [ADR-0017](0017-quaternius-npc-base.md) (2026-11-05)
 - **Date:** 2026-11-03
 
+## Superseded
+
+ADR-0017 replaces the generator-first decision below: Quaternius is now the
+primary NPC base. The evaluation, licence rules and consequences remain as the
+record of the 2026-11-03 decision.
+
 ## Context
 
 The library has eight skinned characters, and role/seed selection reuses them

docs/adr/0017-quaternius-npc-base.md

@@ -0,0 +1,69 @@
+# ADR-0017: Quaternius NPC base
+
+- **Status:** Accepted
+- **Date:** 2026-11-05
+- **Supersedes:** ADR-0015 (generator-first character sourcing)
+
+## Context
+
+The current NPC library is built by the project-owned procedural generator. It
+keeps the contract and ships, but the body, neck, hands and shoes need a
+bespoke part pipeline to read as human. The MakeHuman head and MPFB body
+prototypes improved detail but added a second authoring path, a 19,747-triangle
+prototype and unresolved neck/shoulder seams.
+
+The CC0 **Quaternius Ultimate Modular Characters** pack already provides a
+coherent low-poly human silhouette, 21 modular outfits and 24 animation clips.
+The researched GLBs (`Casual`, `Casual_Hoodie`, `Worker`) measure 4 meshes, 62
+joints and 24 clips each. The owner directed that Quaternius become the NPC
+base. The full evaluation is in [`docs/npc-model-sourcing.md`](../npc-model-sourcing.md).
+
+## Decision
+
+1. **Quaternius is the primary NPC mesh and animation source.** Keep the
+   licence and SHA-256 provenance for the three researched GLBs.
+2. **Stage 1 keeps the runtime contract.** Bake a canonical Quaternius base onto
+   the existing 13-core contract, five tint slots, 24,000/24,000 budget,
+   grounded −Y front and one `npc_base` skinned mesh. Retarget Idle and Walk;
+   discard the combat/gun/sword clips. `NpcAvatar`, gear attach points and the
+   pose composition remain the runtime interface.
+3. **The 62-joint rig is an authoring source, not a runtime dependency.** It is
+   not shipped and Quaternius is not loaded by CI, build or runtime.
+4. **Stage 2 needs its own ADR.** If the proportion warp fails the silhouette,
+   deformation or gear gate, stop and decide whether to adopt the 62-joint rig
+   at runtime. Do not ship a hybrid rig or a second gear offset system.
+5. **Close the MakeHuman/MPFB body work.** The accepted MakeHuman head and the
+   procedural `npc_base` stay as tested fallbacks until the Quaternius rollout
+   ships. No new MPFB development.
+6. **Commit baked assets only.** The release consumes committed GLBs, maps and
+   the manifest; Quaternius and Blender remain development tools.
+
+## Consequences
+
+### Positive
+
+- A human base, modular outfits and a coherent animation set are already
+  authored and CC0.
+- The bespoke neck, hand and shoe pipelines are no longer on the critical path.
+- The runtime contract and gear stay stable during the mesh migration.
+
+### Negative
+
+- A 62-joint T-pose does not share the arm-down 13-core rest pose or
+  proportions; the proportion warp is the main risk.
+- Quaternius' animation quality is only available after retargeting, unless
+  Stage 2 is accepted.
+- The migration touches all 12 variants, their AO maps, manifest entries and
+  baseline captures at once.
+
+## Alternatives
+
+- **Keep the procedural generator as the primary path.** Rejected by the owner:
+  the human silhouette remains the weak point and the bespoke part pipeline is
+  larger than the Quaternius bake.
+- **Adopt the 62-joint rig immediately.** Deferred to Stage 2 because it changes
+  `NpcAvatar`, pose composition and gear offsets at the same time as the mesh.
+- **Continue the MPFB body.** Rejected: it needs a separate head/neck/hand
+  pipeline and still has unresolved surface seams.
+- **Use a service character generator (Mixamo, Ready Player Me).** Rejected:
+  redistribution and runtime terms are not a CC0 basis.

docs/adr/README.md

@@ -20,3 +20,4 @@ Each ADR records the context, decision, consequences and alternatives for a dura
 - [0014-runtime-image-root](0014-runtime-image-root.md)
 - [0015-npc-model-variety-sourcing](0015-npc-model-variety-sourcing.md)
 - [0016-npc-character-budget-24k](0016-npc-character-budget-24k.md)
+- [0017-quaternius-npc-base](0017-quaternius-npc-base.md)