Implemented the deterministic Engine teardown ordering in Engine destructor:

- Pool-owned HTTP clients stop first.
  - The active GL context is made current.
  - Scenes are destroyed before batches and resource managers.
  - Pending batches explicitly discard vertices and borrowed textures.
  - TextLayout cache clears before fonts.
  - Framebuffer/vertex managers and textures are released while Renderer/context remain alive.
  - ShaderProgramManager is destroyed before Renderer.
  - Windows and contexts are destroyed last.

The lifecycle test uncovered and fixed another bug: StaticLRU::clear() retained non-trivial values such as cached shared_ptr<TextLayout> objects. It now releases active values in LRUCache.

.agent/plans/resource_refactor_prerequisite_bugfixes.md

@@ -1,6 +1,6 @@
 # Resource-refactor prerequisite bug fixes
 
-Status: active defect track, 2026-07-12.
+Status: active defect track, updated 2026-07-13.
 
 This document isolates correctness defects discovered during the shared-resource ownership audit.
 They should be fixed before the public resource API refactor wherever practical. Fixes in this track
@@ -86,6 +86,10 @@ Regression coverage:
 - Repeat Engine creation/destruction in the same test process.
 - Assert no callback touches the destroyed scene/factory and no singleton is recreated.
 
+Status: Engine now clears pool-owned HTTP clients before scene/Graphics teardown. The complete
+producer barrier remains pending A2 and A4 because shared-executor operations and static UI
+deliveries do not yet have complete close/reject semantics.
+
 ### A4. UISceneNode static delivery queue lacks shutdown semantics
 
 Current behavior:
@@ -122,21 +126,29 @@ Regression coverage:
 
 - Create/link programs, destroy Engine, and repeat under ASAN.
 
+Status: fixed, 2026-07-13. ShaderProgramManager is destroyed before Renderer while the selected
+window and context are still alive.
+
 ### B2. TextLayout cache destroyed after FontManager
 
 Current behavior:
 
 Cached shaped glyphs retain raw FontTrueType pointers. The global TextLayout cache is currently
-cleared after FontManager destruction.
+cleared after FontManager destruction. `StaticLRU::clear()` also resets only its indexes, leaving
+non-trivial cached values such as shared TextLayout pointers alive in its backing array.
 
 Fix:
 
 - Clear TextLayout and related shaped-font caches before FontManager.
+- Release every active StaticLRU value when clearing the cache.
 
 Regression coverage:
 
 - Populate shaped-layout cache, destroy Engine, and verify repeated Engine lifecycle under ASAN.
 
+Status: fixed, 2026-07-13. TextLayout is cleared before FontManager, and StaticLRU now resets its
+active values. A weak cached layout expires during each tested Engine teardown.
+
 ### B3. Scene/global resource manager order
 
 Current behavior:
@@ -153,6 +165,10 @@ Regression coverage:
 
 - Destroy an Engine with live scene widgets using nine-patches and a non-empty batch.
 
+Status: fixed, 2026-07-13. Scenes are destroyed first, BatchRenderer destruction explicitly drops
+queued vertices and borrowed texture state without GL work, and global drawable/resource managers
+remain alive until scene destruction completes.
+
 ## 4. Priority C: loader and callback lifetime
 
 ### C0. MemoryManager first-use synchronization

.agent/plans/resource_refactor_prerequisite_execution_plan.md

@@ -1,6 +1,7 @@
 # Resource-refactor prerequisite bug-fix execution plan
 
-Status: active; work packages 1 and 2 completed, 2026-07-13.
+Status: active; work packages 1 and 2 completed; Work Package 4 deterministic ordering implemented,
+2026-07-13.
 
 This plan defines the bounded correctness work to complete before Stage 1 of the shared-resource
 ownership refactor. It turns the findings in `resource_refactor_prerequisite_bugfixes.md` into an
@@ -143,6 +144,23 @@ Status: implemented. The focused TSAN suite initially reproduced the race in
 `MemoryManager::addPointer()`. After the fix, all six `ResourcePrerequisites` tests pass under
 TSAN without suppressions. The ASAN build and focused tests also pass.
 
+### 3.6 StaticLRU clear retains non-trivial values
+
+Current defect found during Work Package 4 validation:
+
+`StaticLRU::clear()` resets its hash/list metadata and active count but leaves values in its backing
+array. For `TextLayout::Cache`, this means `TextLayout::clearLayoutCache()` does not release cached
+layouts or their raw font references.
+
+Fix:
+
+- Reset only the active value slots before clearing StaticLRU metadata.
+- Keep the operation proportional to the number of live entries rather than total capacity.
+- Verify cache release through a weak TextLayout handle during repeated Engine teardown.
+
+Status: implemented. The cached layout expires before FontManager destruction in both tested
+Engine lifecycles.
+
 Work-package exit criteria:
 
 - Each fix has an isolated regression test.
@@ -295,6 +313,14 @@ Work-package exit criteria:
 - Every GPU-owning manager is destroyed while its required Renderer/context services remain valid.
 - Repeated Engine lifecycle tests pass.
 
+Status: the deterministic dependency order is implemented. Engine clears pool-owned HTTP clients
+first, makes the selected context current, destroys scenes, explicitly discards batch state, clears
+TextLayout, releases high-level Graphics managers in dependency order, destroys shaders before
+Renderer, and only then destroys windows/contexts. A focused test covers two Engine lifecycles with
+a live UI scene, framebuffer, nine-patch, texture, font/layout cache, shaders, and pending batch.
+The complete asynchronous-producer exit criterion remains pending Work Packages 3 and 5.
+The complete ASAN unit suite passes: 746 tests passed and one opt-in visual test was skipped.
+
 ## 7. Work package 5: UISceneNode async delivery lifecycle
 
 Current behavior:

.agent/plans/resource_shared_ownership_stage0_inventory.md

@@ -342,6 +342,13 @@ TextLayout cache
 SystemFontResolver
 ```
 
+This list records the pre-prerequisite order found by the audit. On 2026-07-13 the deterministic
+portion was corrected: pool-owned HTTP clients stop first; the selected context is made current;
+scenes precede GlobalBatchRenderer and global resource managers; TextLayout precedes FontManager;
+ShaderProgramManager precedes Renderer; and windows/contexts remain until all Graphics singleton
+teardown is complete. Complete shared-executor and static UI-delivery barriers remain assigned to
+their prerequisite work packages.
+
 Concrete violations:
 
 | Current edge/order | Violation |