refactor(streaming): extract the update frame

docs/plans/2026-07-21-gamewindow-slice-6-update-frame-orchestration.md

@@ -18,7 +18,7 @@ never hidden behind a retry, delay, suppression flag, or reordered callback.
 - [x] B — extract the pre-network live-object presentation phase and the
   non-advancing post-network spatial reconciler; remove callbacks into
   `GameWindow` from `RetailLiveFrameCoordinator`.
-- [ ] C — extract streaming-origin convergence, observer selection, dungeon
+- [x] C — extract streaming-origin convergence, observer selection, dungeon
   collapse, streaming tick, and rescued-entity rebucketing.
 - [ ] D — extract dispatcher/raw-mouse/combat input sampling without changing
   movement-command or UI-capture semantics.
@@ -50,6 +50,17 @@ and removed animation/runtime/projectile back-references to `GameWindow`.
 Release tests, the 2,732-test App suite, and the full 7,090-test Release suite
 (5 fixture/environment skips); all three independent reviews are clean.
 
+Checkpoint C moved retained origin convergence, readiness, observer selection,
+sealed-dungeon collapse, streaming publication, and persistent live-projection
+rescue into `StreamingFrameController`. Production keeps streaming publication
+ahead of input and the live object/network barrier, so a same-frame
+CreateObject can enter the newly resident bucket. The focused 146-test Release
+selection, 2,754-test App suite, and complete 7,112-test Release suite (5
+fixture/environment skips) pass. Login-before-position, portal hold, outdoor
+and sealed/SeenOutside EnvCells, pending recenter, exact rescue rebucketing,
+GUID deletion, and session reset are pinned; all three corrected-diff reviews
+are clean. `GameWindow.cs` is now 8,569 raw lines.
+
 ## 1. Outcome and non-goals
 
 At slice exit, `GameWindow.OnUpdate` starts the profiler scope and delegates one