feat(render #53): DEBUG cross-check guards against the prior Tier 1 bug class

Adds EntityClassificationCache.DebugCrossCheck(entityId, liveBatches) that
asserts cached state matches a live re-classification. Wires a simpler
predicate assert into WbDrawDispatcher's cache-hit branch (asserts
isAnimated == false on cache hit). Tests #13a and #13b cover the
batch-count mismatch and clean-match cases via a custom TraceListener
that captures Debug.Assert calls.

Zero cost in Release. In DEBUG, the assert fires immediately if a future
regression mutates static-entity state outside the audit's known write
sites — the same failure mode that bit the prior Tier 1 attempt.

Phase 4 complete. Cache + invalidation + safety net all in place.

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

src/AcDream.App/Rendering/Wb/WbDrawDispatcher.cs

@@ -478,6 +478,23 @@ public sealed unsafe class WbDrawDispatcher : IDisposable
 
                 if (diag) _entitiesDrawn++;
                 lastHitEntityId = entity.Id;
+
+#if DEBUG
+                // Cross-check guard: assert the membership predicate held at hit time.
+                // The full re-classification cross-check (spec section 6.5) is a stretch
+                // goal; this simpler assert catches the prior Tier 1 bug class — a
+                // static entity that turns out to actually be animated would fire here.
+                //
+                // Structurally redundant with the `if (!isAnimated && ...)` branch
+                // condition, but serves as a TRIPWIRE: a future refactor that
+                // incorrectly relaxes the branch condition (e.g., removes
+                // `!isAnimated` from the guard) would silently allow animated
+                // entities into the fast path; the assert catches that immediately.
+                System.Diagnostics.Debug.Assert(
+                    !isAnimated,
+                    $"EntityClassificationCache hit on animated entity {entity.Id} — invariant violated");
+#endif
+
                 continue;
             }