test: replace composition source freezes

docs/reviews/2026-08-18-r3-test-truth-ledger.md

@@ -1208,3 +1208,60 @@ Verification:
   attributed methods, and reduces total direct/helper source readers from 92
   to 83 while direct readers remain 57. The remaining 83 reconcile to the 22
   approved retained policies/contracts and 61 staged replacements.
+
+## Batch Z composition-root source-freeze replacement
+
+Batch Z converts 12 approved source-text readers across the seven graphical
+composition-owner suites and removes one stale backend assertion. No product
+source changes. The replacement tests use the built call graph, reflected
+owner metadata, existing transactional fixtures, and typed composition results
+instead of source fragments.
+
+The exact decisions are:
+
+- all seven phase-boundary tests now prove that `GameWindow` constructs exactly
+  one instance of the relevant composition phase and does not directly
+  construct the leaf owners that belong behind it. The phase and snapshot
+  types are also checked for the absence of a retained `GameWindow` owner;
+- the platform prelude now verifies the compiled `OnLoad` route through
+  `AcquirePlatform` and `GameWindowCompositionPipeline.Run`, plus the single
+  `GameWindowPlatformAcquisition.Acquire` and host/input/camera phase edges;
+- the prepared-asset contract follows the production factory, world phase,
+  `ObjectMeshManager`, `WbMeshAdapter`, and compiled shutdown manifest. It
+  proves one `IPreparedAssetSource` owner, no DAT-reader constructor seam in the
+  production mesh manager, prepared reads rather than live mesh building, and
+  mesh/prepared-source/DAT release order;
+- the frame-root test follows the compiled construction order from render
+  resources and comparison state through the world/update roots, graph
+  publication, window publication, and final ownership transfers. The
+  lifecycle snapshot contract now verifies its exact `RenderFrameOutcome`
+  input and its typed live-entity, GPU-memory, profiler, and landblock metrics;
+- the session phase follows the compiled streamer/start/reveal route and the
+  delegate target that constructs the request streamer. Its completion check
+  follows hydration, inbound routing, input/player mode, portal transfer,
+  session creation, command bindings, action attachment, and final publication
+  in order. Character selection now verifies the graphical selector option,
+  typed connect options, absence of automatic first-character selection, and
+  retained-UI runtime bindings;
+- the interaction, live-presentation, and world-render boundaries retain their
+  existing behavioral phase fixtures while compiled metadata guards against
+  construction leaking back into `GameWindow`; and
+- `PortalSpaceIsComposedOnBothBackendArms` is removed as stale. Campaign V
+  deleted the OpenGL backend, so a two-backend-arms source condition is no
+  longer an architectural contract; its negative assertion named an already
+  deleted null presentation. The valuable portal ownership rationale remains
+  in the live/session composition code, the compiled portal transfer order,
+  and the existing teleport/reveal behavior suites.
+
+Verification:
+
+- all 187 composition tests pass with zero skips or failures;
+- the complete locked Release build covers all 44 projects with zero warnings
+  and zero errors;
+- the no-retry complete hermetic Release gate passes 14,346/14,346 with zero
+  skips or failures across all 12 test assemblies. The one-case reduction is
+  the stale two-backend-arms assertion; and
+- the regenerated 1,254-file inventory parses every file, reports 11,414
+  attributed methods, and reduces direct/total source readers from 57/83 to
+  44/70. The remaining 70 reconcile to the 22 approved retained
+  policies/contracts and 48 staged replacements.