perf(content): close prepared asset cutover

docs/plans/2026-07-24-modern-runtime-slice-c-prepared-assets.md

@@ -2,15 +2,18 @@
 
 **Date:** 2026-07-24
 
-**Status:** active — C1 and C2 landed; C3 implemented, C4 connected gate next
+**Status:** complete — automated, connected, performance, and user visual
+gates passed 2026-07-24
 
 **Checkpoint ledger:**
 
 - C1 typed prepared-source boundary — `c42f93b3`
 - C2 production renderer injection — `f05afc07`
 - C3 activation probes and lookup precedence — `230a7df4`; automated gate
-  green, connected exception-count gate remains in C4
-- C4 connected equivalence and performance closeout — pending
+  green
+- C4 prepared-source diagnostics — `b1ad4b7c`
+- C4 connected equivalence and performance closeout —
+  [`../research/2026-07-24-slice-c-prepared-asset-cutover-report.md`](../research/2026-07-24-slice-c-prepared-asset-cutover-report.md)
 
 **Parent:** [`2026-07-24-modern-runtime-architecture.md`](2026-07-24-modern-runtime-architecture.md),
 Slice C / MP1c
@@ -300,6 +303,32 @@ If pixels or behavior differ, the slice is not complete even when performance
 improves. If timing improves but heap reservation still fails, keep the failure
 open and attribute it before considering Slice C closed.
 
+### C4 result — completed 2026-07-24
+
+The format-1/bake-tool-3 production package validated with 751,141 keys and
+the exact installed DAT iterations. Installed-DAT seam/equivalence tests, all
+three connected physical-display routes, canonical lifetime assertions, and
+the complete Release suite passed. The user accepted the prepared path's
+geometry, materials, textures, and world presentation.
+
+Against the committed Slice A physical baseline:
+
+- capped CPU p95/p99 improved 15.8%/16.9%, GPU p95/p99 17.4%/20.0%;
+- uncapped CPU p95/p99 improved 13.8%/17.0%, GPU p95/p99 22.5%/20.6%;
+- dense-Arwic CPU/GPU p99 improved 12.0%/16.8%;
+- process allocation fell 54.9% capped, 41.8% uncapped, and 61.9% dense;
+- GC pause time fell 52.8%, 48.4%, and 54.1%;
+- the invalid typed-Setup exception count fell to zero in every route;
+- the largest frame-thread allocation fell from roughly 203 MiB to 46.8 MiB
+  capped and 39.9 MiB uncapped;
+- both warm repeated-Caul memory comparisons passed the unchanged assertion.
+
+Windows reports clean memory-mapped package pages in working set, so total
+working set is higher even though private memory and ownership remain bounded.
+That is file cache, not retained world state. Exact measurements and the
+artifact policy are recorded in the
+[Slice C report](../research/2026-07-24-slice-c-prepared-asset-cutover-report.md).
+
 ## 4. Review checklist per checkpoint
 
 Because this task is running without delegated reviewers, the primary engineer