refactor(simulation): rename DistrictSkeleton→QuarterSkeleton per D-222 (#950)

D-222 renamed the 512m generation cell from District to Quarter (District
is now a new 2048m tier above it). Align the generation skeleton code to
the canonical vocabulary. Pure naming — no behavior change; all 1296 lib
tests + integration tests pass unchanged.

Renamed (spatial-cell identifiers):
- DistrictSkeleton → QuarterSkeleton, DistrictWorldState → QuarterWorldState
- DistrictId → QuarterId, DistrictContext/DistrictBoundaries → Quarter*
- field district_id → quarter_id, district_type → quarter_type
- BodyWorldState.districts map → .quarters
- generate_skeleton → generate_quarter_skeleton

Deliberately left as-is (these name functional ZONING, not the spatial
tier — orthogonal to D-222): DistrictType, DistrictLayoutMode, the
district_mix module (DistrictMix/compute_district_mix), and the
GenWorkItem::GenerateSkeleton / GenCompletion::SkeletonGenerated variants.

Also aligned the perception "sim tile" → "subtile" vocabulary (D-222:
Subtile = 0.5m) in decisions/perception.md and the generation-cascade code
comments. Historical D-066/D-094/D-201/D-220 decision bodies keep their
existing D-222 amendment notes (not rewritten in place); the public
max_offset_sim_tiles fn name is unchanged.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

decisions/perception.md

@@ -149,7 +149,7 @@ How the player observes and interacts with the world: camera, fog, line-of-sight
 ### D-044: Art direction — visual hierarchy (entity > object > structure)
 - **Date:** 2026-02-12
 - **Decision:** Three-layer visual hierarchy: entities (2px outline, D-033 relationship color, highest saturation) > objects (1px outline, era-appropriate palette, moderate saturation) > structure (minimal/no outline, muted zone palette, lowest saturation). Hard rendering rule: entity always wins visual ties — if an entity and object overlap, the entity's D-033 color must remain visible. This is a readability guarantee, not an aesthetic preference.
-- **Entity spec:** 24x32 pixel footprint within 64x64px visual tiles. Entities occupy 1x1 sim tiles (0.5m) but render across a 2x2 sim tile sprite footprint per [D-066](architecture.md#d-066-dual-scale-grid--05m-simulation-1m-visual-2x-retina-factor). D-033 color as primary information signal, silhouette as primary identity signal. One identifying silhouette feature per named NPC (Kael's vest, Lera's apron, Sera's uniform). 3-4 template silhouettes for generic NPCs.
+- **Entity spec:** 24x32 pixel footprint within 64x64px visual tiles. Entities occupy 1x1 subtiles (0.5m) but render across a 2x2 subtile sprite footprint per [D-066](architecture.md#d-066-dual-scale-grid--05m-simulation-1m-visual-2x-retina-factor). D-033 color as primary information signal, silhouette as primary identity signal. One identifying silhouette feature per named NPC (Kael's vest, Lera's apron, Sera's uniform). 3-4 template silhouettes for generic NPCs.
 - **Canonical reference:** `docs/workshops/art-direction-mood-board/workshop-outcomes.md` §1.4, §1.5
 - **Raised by:** Araminta (outline spec), Ozzie (readability priority). Unanimously endorsed.
 - **Dissent:** None
@@ -212,7 +212,7 @@ How the player observes and interacts with the world: camera, fog, line-of-sight
   - **Object hover:** Ticks rotate 45° to X-shape. Muted grey #8b8ba0 (amber #e8c547 if flagged). Simpler frame than entity.
   - **Weapon aim:** Hard transition. Ticks extend, center gap widens, lines thicken 1→2px. Warm white #f0e8d8. NO bloom. Entity in sights tints to D-033 color — aiming at a friend (green tint) should feel wrong.
 - All transitions 150ms linear. z-layer 7. Never changes by zone or narrative state ([D-045](#d-045-art-direction--environmental-neutrality-strict-zero-shift)).
-- Cursor changes on LOS, not just proximity. Click interaction range: ~2 sim tiles (= 1m per [D-066](architecture.md#d-066-dual-scale-grid--05m-simulation-1m-visual-2x-retina-factor)). Weapon-selected mode suppresses interaction prompts unless Shift held ("combat intent trumps social intent").
+- Cursor changes on LOS, not just proximity. Click interaction range: ~2 subtiles (= 1m per [D-066](architecture.md#d-066-dual-scale-grid--05m-simulation-1m-visual-2x-retina-factor)). Weapon-selected mode suppresses interaction prompts unless Shift held ("combat intent trumps social intent").
 - **Diegetic test (Stig):** Interaction labels render on z-layer 6 (insert overlay). If the insert is off, labels disappear. Passes the "is this information from the character's implant?" test.
 - **Rationale:** Diegetic — cursor is the insert's own interface element. Consistent with [D-048](#d-048-neural-insert-overlay--visual-design). Entity in weapon sights tinting to D-033 creates moral friction.
 - **Cross-reference:** Insert overlay ([D-048](#d-048-neural-insert-overlay--visual-design)), entity color ([D-033](#d-033-entity-color--relationship-to-player)), z-stack ([D-049](#d-049-z-level-rendering-stack-8-layers))
@@ -254,7 +254,7 @@ How the player observes and interacts with the world: camera, fog, line-of-sight
 ### D-059: Fog — shader-based, five layers, knowledge-graph-driven
 - **Date:** 2026-02-13
 - **Decision:** Fog is a shader-driven system (not particles) with five distinct layers:
-  1. **Clear (vision cone):** Soft gradient edge over 6-8 sim tiles (= 3-4 visual tiles per [D-066](architecture.md#d-066-dual-scale-grid--05m-simulation-1m-visual-2x-retina-factor)), no hard line. Darkwood approach.
+  1. **Clear (vision cone):** Soft gradient edge over 6-8 subtiles (= 3-4 visual tiles per [D-066](architecture.md#d-066-dual-scale-grid--05m-simulation-1m-visual-2x-retina-factor)), no hard line. Darkwood approach.
   2. **Light fog (peripheral):** Desaturated 40-50%, brightness -30%. Animated Perlin noise overlay (8-10s cycle). Entity [D-033](#d-033-entity-color--relationship-to-player) colors visible but reduced.
   3. **Deep fog (previously explored):** Near-monochrome with ~10% "zone temperature" tint (bar=warm dark, hub=cool dark, corridor=neutral dark). More pronounced noise (15-20s cycle). Fog breathes.
   4. **Unexplored + maps app:** Geometric wireframe outlines #333340. Insert data aesthetic.