docs(architecture): reconcile GameWindow extraction program

Close the completed M3 and portal observer gates, make the behavior-preserving GameWindow ownership campaign the explicit M4 prerequisite, and replace the stale extraction sketch with an implementation-audited sequence.

Co-authored-by: OpenAI Codex <codex@openai.com>

docs/ISSUES.md

@@ -24,12 +24,12 @@ What does NOT go here:
 - Every session: scan OPEN issues at start; promote/close anything we touched during the session before ending.
 - Promoting to a Phase: mark as `DONE (promoted to Phase X)` + commit SHA where the Phase entry landed.
 
-## Current queue — 2026-07-20
+## Current queue — 2026-07-21
 
-- **Next visual gate:** R6 locomotion/collision/projectile/teleport comparison
-  after the complete-root-Frame/object-workset cutover.
-- **M3 closing gate:** `#218`, final two-client portal-out/materialization and
-  indoor observer comparison.
+- **Active structural work:** `GameWindow` decomposition, beginning with the
+  selection/interaction ownership slice in
+  [`docs/architecture/code-structure.md`](architecture/code-structure.md).
+  This is the behavior-preserving prerequisite before new M4 feature bodies.
 - **Separate rendering gate:** `#225`, lifestone/particle alpha ordering. Its
   connected performance, lifetime, and unattended portal routes pass.
 - **Carried behavior debt:** `#153` far-teleport unstreamed-edge arrival and
@@ -98,7 +98,7 @@ production runtime failure.
 
 **Acceptance:** A non-incremental Release solution build reports zero warnings
 and zero errors without suppressing analyzers or weakening nullable checking;
-the full 6,480-pass / 5-skip suite remains green.
+the full 6,481-pass / 5-skip suite remains green.
 
 ---
 
@@ -565,7 +565,7 @@ Passed 2026-07-17: “Yes works.”
 
 ## #218 — Portal silhouette pose, destination reveal, and indoor observer snap
 
-**Status:** IN-PROGRESS — root fixes implemented 2026-07-16; pending connected visual gate
+**Status:** DONE — 2026-07-21, final two-client observer gate user-confirmed
 **Severity:** HIGH
 **Filed:** 2026-07-16
 **Component:** portal VFX / streaming / physics / outbound movement
@@ -635,6 +635,9 @@ pose; outdoor exits reveal only fully rendered terrain/scenery; and a retail
 observer sees acdream run and stop repeatedly inside a dungeon without any
 snap back to the entrance.
 
+**Gate:** Passed 2026-07-21. The user confirmed the final two-client
+portal-out/materialization and indoor observer comparison on the R6 baseline.
+
 ---
 
 ## #217 — Character windows did not receive live 64-bit experience updates