Docs: session log Part P + roadmap tick + CLAUDE.md gotcha — Phase 1.5b decals bundle shipped

Bundle 2 (decals): explosion scorch pool, cover damage-cracks, room-arena
scars — all procedural, client-only, zero netcode. Records the pivotal
finding that a stock Synty prop shadergraph's _BaseColor is Unity-Per-Material
(not Hybrid-Per-Instance), so URPMaterialPropertyBaseColor darkening silently
no-ops on cover — the fork to decal quads.

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

Docs/Vault/06_Roadmap/Iteration_2026-07_CoopHades.md

@@ -168,8 +168,14 @@ plain"** — expand 1.5 before 1.7. Locked bundles, sequenced ground-first:
    per room inside the room's ACTUAL shape (hash stream 0xD2E55; 47 build-safe prefab refs), room-torn-down;
    live-verified incl. teardown + exact Meadow tint convergence; (c) worn paths storage→warpgate/base-gate;
    (d) 357 base flora re-enabled (buildings/pond/FX stay parked).
-2. **Decals**: dynamic explosion scorch marks (fading quad pool at boom sites), static POI scorch/cracks,
-   cover damage-crack states (URPMaterialPropertyBaseColor darkening keyed on replicated Remaining).
+2. ✅ **Decals** (SHIPPED, Part P — all procedural, client-only, zero netcode): explosion scorch pool
+   (fading disc pool via `ScorchDecalSystem.RequestScorch`, wired from the barrel boom; reusable by the
+   geyser) · cover damage-CRACKS keyed on replicated `BlightClutter.Remaining` (Variant 4) + proximity-gated
+   shatter-scorch · light room-arena crack/scorch scars (via `RoomDressingSystem`). ★ The specified
+   `URPMaterialPropertyBaseColor` darken would have **silently no-op'd** — cover's Synty `Generic_Basic`
+   shadergraph declares `_BaseColor` Unity-Per-Material, NOT Hybrid-Per-Instance (only the DOTS-authored
+   `AnimatedLitShader` honours the EG per-instance override); operator fork → decal quads instead. Base POIs
+   skipped (Part O baked their wear). Knobs in `DecalConfig`.
 3. **Hazard variant**: Blight geyser (periodic both-sides AoE on the HazardExplosion + telegraph-disc
    chassis) — mini design review first (new replicated erupt-phase surface).
 4. **Critters + weather beats**: fleeing bugs/birds; cloud-shadow drifts; Blight lightning flicker.