perf(content): close prepared asset cutover

AGENTS.md

@@ -130,6 +130,18 @@ user-accepted. Favorite-spell press-time selection and right-click local
 examination are implemented; the current visual gate is its corrected modern
 scarab/prismatic formula, DAT component icons, and authored 310 x 400 extent.
 
+**Active performance side track:** Slices A–C of
+`docs/plans/2026-07-24-modern-runtime-architecture.md` completed 2026-07-24.
+Production world-mesh streaming now consumes the validated machine-local
+`acdream.pak` through `IPreparedAssetSource`; live DAT extraction remains
+explicit bake/equivalence/UI-Studio tooling. Capped, uncapped, dense-Arwic,
+lifetime, full-suite, and user-visual gates passed. Process allocation fell
+41.8–61.9%, GC pause time fell 48.4–54.1%, uncapped CPU/GPU p99 improved
+17.0%/20.6%, and invalid Setup-probe exceptions fell to zero. Slice D (typed
+handles and unified residency accounting) is next; ECS/MP3 remains behind its
+explicit user decision gate. Evidence:
+`docs/research/2026-07-24-slice-c-prepared-asset-cutover-report.md`.
+
 **Structural prerequisite before new M4 subsystem work:** all eight
 behavior-preserving `GameWindow` decomposition slices and the automated
 closeout landed 2026-07-22. The class is now a 1,622-line native
@@ -149,7 +161,7 @@ uncapped Release presentation is smooth, while physics, collision, and wire
 truth remain correct.
 See `docs/plans/2026-07-22-gamewindow-slice-8-composition-lifecycle.md` and
 `docs/architecture/code-structure.md`. **Carried:** #153, #116, remaining
-R6 ownership cleanup, TS-50/TS-51/TS-53, Modern Pipeline MP1b+, and #225's
+R6 ownership cleanup, TS-50/TS-51/TS-53, Modern Runtime Slice D+, and #225's
 lifestone/particle alpha visual gate.
 
 Start structural work at `memory/project_gamewindow_decomposition.md` and