refactor(web): extract allocation multi-drag session

scripts/check-architecture-guardrails.mjs

@@ -251,6 +251,17 @@ export const rules = [
     ],
     forbidden: [],
   },
+  {
+    file: "apps/web/src/hooks/timelineAllocationMultiDragSession.ts",
+    maxLines: 90,
+    required: [
+      {
+        pattern: /\bexport function beginAllocationMultiDragSession\b/,
+        message: "timeline allocation multi-drag session helpers must keep document drag lifecycle centralized",
+      },
+    ],
+    forbidden: [],
+  },
   {
     file: "apps/web/src/hooks/timelineAllocationActions.ts",
     maxLines: 90,
@@ -410,6 +421,10 @@ export const rules = [
         pattern: /from "\.\/timelineAllocationMultiDrag\.js"/,
         message: "timeline drag must keep allocation multi-drag rules delegated to the extracted helper module",
       },
+      {
+        pattern: /from "\.\/timelineAllocationMultiDragSession\.js"/,
+        message: "timeline drag must keep allocation multi-drag document session wiring delegated to the extracted helper module",
+      },
       {
         pattern: /from "\.\/timelineAllocationDragState\.js"/,
         message: "timeline drag must keep allocation drag bootstrap delegated to the extracted helper module",
@@ -460,6 +475,10 @@ export const rules = [
         pattern: /\bfunction (?:isAllocationMultiSelected|startAllocationMultiDrag|updateAllocationMultiDrag|finalizeAllocationMultiDrag)\b/,
         message: "timeline drag must not re-inline extracted allocation multi-drag helper implementations",
       },
+      {
+        pattern: /\bfunction handleMulti(?:Move|Up)\b/,
+        message: "timeline drag must not re-inline extracted allocation multi-drag session handlers",
+      },
       {
         pattern: /\bfunction createAllocationDragState\b/,
         message: "timeline drag must not re-inline extracted allocation drag bootstrap helpers",