docs: Campaign LA LA0 DONE — ledger closed; arch-doc wording nit from narrow re-review

The re-review closed all six findings and flagged one docs-only nit: the
Platform layer block described App as reaching Platform transitively when
the same commit made the reference direct, and spoke of the launcher in
the present tense. Both corrected.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

docs/architecture/acdream-architecture.md

@@ -277,9 +277,11 @@ src/
                                 plugin, screenshot, and diagnostic paths
     -> zero project/package references (guarded by
        tests/AcDream.Platform.Tests/PlatformDependencyBoundaryTests.cs);
-       Runtime references it and re-exports transitively to App/Headless;
-       the external launcher (AcDream.Launcher.Core) references ONLY this
-       project from the game solution
+       Runtime and App reference it directly; Headless reaches it
+       transitively through Runtime (K0 guard: Headless declares exactly
+       one project reference); the external launcher (AcDream.Launcher.Core,
+       Campaign LA — under construction) references ONLY this project from
+       the game solution
 
   AcDream.Headless/          Linux/Windows no-window production host
     Program.cs               -> CLI entry only