Bind Win32 tablet state in runtime shell

docs/modernization/roadmap.md

@@ -92,6 +92,14 @@ Current hotspot files:
 
 Latest slice:
 
+- The Win32 stylus and pointer-input path no longer reaches
+  `WacomTablet::I` directly inside
+  `src/platform_windows/windows_window_shell.cpp` or
+  `src/platform_windows/windows_stylus_input.cpp`; the live Windows runtime
+  shell now binds the active tablet explicitly through
+  `src/platform_windows/windows_runtime_shell.*`, leaving
+  `WacomTablet::I` only at the entry composition edge where the runtime shell
+  binds the active tablet instance.
 - The remaining dense Windows bootstrap singleton pocket moved off
   `App::I`: `setup_exception_handler(...)`, `initialize_main_window_startup_state(...)`,
   and `_pre_call_callback(...)` now use explicit app/bound-runtime state

docs/modernization/tasks.md

@@ -56,8 +56,11 @@ Completed, blocked, and superseded task history moved to
   - canvas async import/export/save/open now run through an owned in-file
     worker, but their retained progress execution is still not a clean runtime
     service boundary
-  - thread-affinity rules are enforced by convention and asserts instead of
-    explicit runtime contracts
+  - the Win32 input path now binds the active `WacomTablet*` explicitly
+    through `windows_runtime_shell`, but that tablet binding still lives at a
+    composition edge instead of a broader runtime/platform-owned controller
+    - thread-affinity rules are enforced by convention and asserts instead of
+      explicit runtime contracts
 - The UI ownership boundary is not finished:
   - base `Node` still carries raw parent/manager pointers beside shared handles
   - callback captures still frequently close over retained nodes and `App::I`
@@ -1202,6 +1205,13 @@ Why now:
 platform-handle state on `App`, which blocks a real `pp_platform_*` shell split.
 
 Current slice:
+- The Win32 stylus and pointer-input path no longer reaches
+  `WacomTablet::I` directly in
+  `src/platform_windows/windows_window_shell.cpp` or
+  `src/platform_windows/windows_stylus_input.cpp`;
+  `src/platform_windows/windows_runtime_shell.*` now binds the active tablet
+  explicitly and the touched consumers read it through that runtime-shell
+  binding instead of the process-global singleton.
 - The remaining dense Windows bootstrap singleton pocket moved off
   `App::I`: `setup_exception_handler(...)`,
   `initialize_main_window_startup_state(...)`, and `_pre_call_callback(...)`