Thin retained app and render runtime seams

docs/modernization/debt.md

@@ -18,6 +18,24 @@ agent or engineer to remove them without reconstructing context from chat.
 
 ## Reductions
 
+- 2026-06-17: `DEBT-0036` was narrowed again. Retained `Shape`,
+  `src/shader.cpp`, and `src/font.cpp` now queue render-thread create/update/
+  destroy work through `src/renderer_gl/render_runtime_dispatch.h` instead of
+  calling `App::I` directly, and `Shader` render-thread entry points now assert
+  that explicit runtime contract while shader-program and mesh ownership remain
+  retained.
+- 2026-06-17: `DEBT-0036` was narrowed again. `NodeStrokePreview` no longer
+  owns static worker-thread, queue, or render-mutex state directly;
+  `src/legacy_node_stroke_preview_runtime_services.*` now owns the retained
+  preview worker lifecycle and queue helpers, leaving the node as a thinner
+  adapter while the retained preview runtime still reaches app/render helpers
+  internally.
+- 2026-06-17: `DEBT-0029` was narrowed again.
+  `LegacyFileMenuServices::pick_image_for_import()` in
+  `src/legacy_app_shell_services.cpp` now delegates retained import execution
+  to `src/legacy_document_image_import_services.*`, so the File-menu adapter no
+  longer defines the live `DocumentImageImportServices` implementation inline;
+  legacy `Image` loading and retained canvas/import-mode execution still remain.
 - 2026-06-17: `DEBT-0003` was narrowed again. `src/app_runtime.cpp` and
   `src/app_runtime.h` now synchronize render/UI worker running state, reject
   cross-thread work once those workers stop, and drain queued work through