refactor(web): split touch canvas adapters

scripts/check-architecture-guardrails.mjs

@@ -127,10 +127,6 @@ export const rules = [
         pattern: /\bexport function getTouchPoint\b/,
         message: "timeline touch helpers must keep touch coordinate fallback centralized",
       },
-      {
-        pattern: /\bexport function createTouchMouseDownEvent\b/,
-        message: "timeline touch helpers must keep touch-to-mouse adapter wiring centralized",
-      },
       {
         pattern: /\bexport function resolveTouchDragDecision\b/,
         message: "timeline touch helpers must keep scroll-vs-drag disambiguation centralized",
@@ -138,6 +134,21 @@ export const rules = [
     ],
     forbidden: [],
   },
+  {
+    file: "apps/web/src/hooks/timelineTouchAdapters.ts",
+    maxLines: 60,
+    required: [
+      {
+        pattern: /\bexport function createTouchMouseDownEvent\b/,
+        message: "timeline touch adapter helpers must keep touch-to-mouse adapter wiring centralized",
+      },
+      {
+        pattern: /\bexport function createTouchCanvasPointerEvent\b/,
+        message: "timeline touch adapter helpers must keep canvas pointer adapter wiring centralized",
+      },
+    ],
+    forbidden: [],
+  },
   {
     file: "apps/web/src/hooks/timelineMultiSelect.ts",
     maxLines: 90,
@@ -307,6 +318,10 @@ export const rules = [
         pattern: /from "\.\/timelineTouch\.js"/,
         message: "timeline drag must keep touch fallback and drag disambiguation delegated to the extracted helper module",
       },
+      {
+        pattern: /from "\.\/timelineTouchAdapters\.js"/,
+        message: "timeline drag must keep touch pointer adapter wiring delegated to the extracted helper module",
+      },
       {
         pattern: /from "\.\/timelineMultiSelect\.js"/,
         message: "timeline drag must keep multi-select rectangle lifecycle delegated to the extracted helper module",
@@ -354,8 +369,8 @@ export const rules = [
         message: "timeline drag must not re-inline touch coordinate fallback helpers",
       },
       {
-        pattern: /as unknown as React\.MouseEvent/,
-        message: "timeline drag must not re-inline synthetic touch mouse-down adapters",
+        pattern: /as (?:unknown as )?React\.MouseEvent/,
+        message: "timeline drag must not re-inline synthetic touch pointer adapters",
       },
       {
         pattern: /\bfunction (?:hasAllocationDateChange|shouldTreatAllocationDragAsClick|requiresAllocationFragmentExtraction|buildAllocationMovedSnapshot|reconcileOptimisticEntries)\b/,