docs(B.4c): ship handoff + close #58 + file #61 #62 + roadmap/CLAUDE update

Phase B.4c shipped end-to-end 2026-05-13. Holtburg inn doorway
double-click verified: door visually swings open, player walks
through, door visually swings closed.

4 implementation commits:
- B.4c Task 1: door spawn-time AnimationSequencer with state-seeded cycle
- B.4c Task 2: [door-cycle] diagnostic in OnLiveMotionUpdated
- B.4c Task 2 review: IsDoorName shared predicate + durable comment + UM locals
- B.4c stance fix: NonCombat = 0x3D (not 0x01); read spawn.MotionState

Closes #58. Files:
- #61 (AnimationSequencer link->cycle frame-0 flash; visible as brief
  flap at end of door swing; low-severity polish)
- #62 (PARTSDIAG null-guard for sequencer-driven entities; latent
  not currently reachable for doors)

Memory file project_interaction_pipeline.md updated outside the repo.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

CLAUDE.md

@@ -619,17 +619,22 @@ acdream's plan lives in two files committed to the repo:
 
 **Currently in Phase L.2 (Movement & Collision Conformance).** L.2a slices
 1+2+3 + L.2d slice 1+1.5 + L.2g slice 1 + L.2g slice 1b + L.2g slice 1c +
-**Phase B.4b** all shipped and visual-verified 2026-05-13. The M1 demo
-target *"open the inn door"* is met: double-click a door in the Holtburg
-inn doorway → `WorldPicker.Pick` finds the door entity → `BuildUse` sends
-`0xF7B1/0x0036` to ACE → ACE broadcasts `SetState (0xF74B)` with `ETHEREAL`
-bit → `ShadowObjectRegistry.UpdatePhysicsState` (L.2g slice 1) mutates the
-cached state (via fixed ServerGuid→entity.Id translation, L.2g slice 1c) →
-`CollisionExemption.ShouldSkip` exempts on ETHEREAL-alone (L.2g slice 1b) →
-player walks through. Issue #57 (B.4 handler gap) is closed. Issue #58
-(door swing animation — `UpdateMotion 0xF74D` routing for non-creature
-entities) is filed as M1-deferred polish.
+**Phase B.4b** + **Phase B.4c** all shipped and visual-verified 2026-05-13.
+The M1 demo target *"open the inn door"* is met **with full visual feedback**:
+double-click a door in the Holtburg inn doorway → `WorldPicker.Pick` finds
+the door entity → `BuildUse` sends `0xF7B1/0x0036` to ACE → ACE broadcasts
+`SetState (0xF74B)` with `ETHEREAL` bit → `ShadowObjectRegistry.UpdatePhysicsState`
+(L.2g slice 1) mutates the cached state (via fixed ServerGuid→entity.Id
+translation, L.2g slice 1c) → `CollisionExemption.ShouldSkip` exempts on
+ETHEREAL-alone (L.2g slice 1b) → player walks through → door swing animation
+plays (B.4c: spawn-time `AnimationSequencer` registration + `OnLiveMotionUpdated`
+routing for door entities). Issue #57 (B.4 handler gap) is closed. Issue #58
+(door swing animation) is closed by B.4c. Issues #61 (link→cycle boundary
+flash) and #62 (PARTSDIAG null-guard) are filed as M1-deferred polish.
 
+**B.4c ship handoff:** [`docs/research/2026-05-13-b4c-shipped-handoff.md`](docs/research/2026-05-13-b4c-shipped-handoff.md)
+— full evidence for the 4 commits + 2 bonus discoveries (stance-value wrong
+`0x01` vs `0x3D` causing underground doors; link→cycle boundary flash).
 **B.4b ship handoff:** [`docs/research/2026-05-13-b4b-shipped-handoff.md`](docs/research/2026-05-13-b4b-shipped-handoff.md)
 — full evidence for the 9 commits + 4 bonus discoveries (double-click dead
 code, DoubleClick gate, CollisionExemption, ServerGuid→Id translation).
@@ -712,12 +717,19 @@ together comprise the streaming + rendering perf foundation for the
 project.
 
 **Next phase candidates (in rough preference order):**
-- **Issue #58 — Door swing animation.** Route `UpdateMotion (0xF74D)` to
-  non-creature entities so the door visually swings when opened. M1 polish
-  but not blocking. Scope unknown until a spike: could be 30 min (simple
-  routing) or 2 hrs (AnimationSequencer audit for creature-specific
-  assumptions). Start with a spike in `OnLiveMotionUpdated` to see how
-  far the AnimationSequencer cooperates with non-creature entities.
+- **"Click an NPC" verification spike (M1 critical path).** B.4b's
+  `WorldPicker` + `BuildUse` is already wired. The question is whether ACE
+  NPCs respond to a Use message from our testaccount and what they broadcast
+  back (TalkDirect? MoveToObject?). Spike: stand near a Holtburg NPC,
+  double-click, read what ACE sends back. If ACE responds with recognizable
+  packets, wire the handlers; if it is silent, investigate ACE's NPC handler
+  configuration. ~30 min spike, outcome determines whether NPC interaction
+  needs a full phase or is a one-commit fix.
+- **Phase B.5 — Ground item pickup (F key) (M1 critical path).** The
+  `SelectionPickUp` input action + F-key binding exist in `KeyBindings` but
+  `OnInputAction` has no case for it. `BuildUse` IS `BuildPickUp` (same wire
+  format). One-commit addition: add `SelectionPickUp` case to `GameWindow.
+  OnInputAction` → call `InteractRequests.BuildPickUp(seq, _selectedGuid)`. ~30 min.
 - **Triage the chronic open-issue list** in `docs/ISSUES.md` — #2 (lightning),
   #4 (sky horizon-glow), #28 (aurora), #29 (cloud thinness), #37 (humanoid
   coat), #41 (remote-motion blips) have been open since April/early-May and
@@ -732,6 +744,12 @@ project.
   only if user wants sustained 500+ FPS. With Tier 1 dispatcher at ~1.2 ms
   the project comfortably hits 200-400 FPS at radius=12 standstill;
   escalation is optional from here.
+- **Issue #61 — AnimationSequencer link→cycle boundary flash** (M1-deferred
+  polish). Brief flap at end of door-swing animations. Low severity; does
+  not block M1 demo. Address before milestone demo record if distracting.
+- **Issue #62 — PARTSDIAG null-guard** (trivial latent fix). One-line
+  null-coalescing guard in `GameWindow.TickAnimations`. Address any time a
+  diagnostic-related PR is open nearby.
 
 **Earlier rendering + streaming arc (2026-05-08 → 2026-05-10).**
 Phases **N.4 → N.5 → N.5b → A.5** shipped the modern rendering