Own Windows tablet path and thin legacy web fallback

docs/modernization/roadmap.md

@@ -70,6 +70,13 @@ What is already real:
 - `pp_app_core`
 
 Latest slice:
+- `src/platform_windows/windows_runtime_shell.cpp` now owns the Windows tablet
+  object directly; the composition edge no longer binds `&WacomTablet::I` into
+  the Windows runtime path.
+- `src/platform_legacy/legacy_platform_state.*` now exposes narrow Web helper
+  functions for the touched publish/flush/default-canvas/prepared-file paths,
+  so less of the Web fallback behavior lives inline in the legacy platform
+  singleton implementation.
 - `src/platform_windows/windows_runtime_shell.cpp` no longer keeps a separate
   retained `AppRuntime*` binding; the touched Windows shell and platform
   helpers now derive runtime ownership directly from the owned `App`.

docs/modernization/tasks.md

@@ -78,6 +78,13 @@ Completed, blocked, and superseded task history moved to
   the queue is now ordered by code movement instead.
 
 Current slice:
+- `src/platform_windows/windows_runtime_shell.cpp` now owns the Windows tablet
+  object directly, removing the composition-edge `WacomTablet::I` binding from
+  the touched Windows runtime path.
+- `src/platform_legacy/legacy_platform_state.*` now exposes narrow Web helper
+  functions for the touched publish/flush/default-canvas/prepared-file paths,
+  so less of that fallback behavior stays inline in the legacy platform
+  singleton.
 - `src/platform_windows/windows_runtime_shell.cpp` no longer keeps a separate
   retained `AppRuntime*`; the touched Windows lifecycle and main-thread task
   dispatch paths now derive runtime ownership directly from the owned app.