refactor(web): extract allocation multi-drag helpers

scripts/check-architecture-guardrails.mjs

@@ -198,6 +198,25 @@ export const rules = [
     ],
     forbidden: [],
   },
+  {
+    file: "apps/web/src/hooks/timelineAllocationMultiDrag.ts",
+    maxLines: 90,
+    required: [
+      {
+        pattern: /\bexport function isAllocationMultiSelected\b/,
+        message: "timeline allocation multi-drag helpers must keep multi-selection eligibility centralized",
+      },
+      {
+        pattern: /\bexport function updateAllocationMultiDrag\b/,
+        message: "timeline allocation multi-drag helpers must keep same-day delta suppression centralized",
+      },
+      {
+        pattern: /\bexport function finalizeAllocationMultiDrag\b/,
+        message: "timeline allocation multi-drag helpers must keep reset-on-release behavior centralized",
+      },
+    ],
+    forbidden: [],
+  },
   {
     file: "apps/web/src/hooks/useTimelineDrag.ts",
     required: [
@@ -225,6 +244,10 @@ export const rules = [
         pattern: /from "\.\/timelineAllocationFinalize\.js"/,
         message: "timeline drag must keep allocation drag completion rules delegated to the extracted helper module",
       },
+      {
+        pattern: /from "\.\/timelineAllocationMultiDrag\.js"/,
+        message: "timeline drag must keep allocation multi-drag rules delegated to the extracted helper module",
+      },
     ],
     forbidden: [
       {
@@ -239,6 +262,10 @@ export const rules = [
         pattern: /\bfunction (?:hasAllocationDateChange|shouldTreatAllocationDragAsClick|requiresAllocationFragmentExtraction|buildAllocationMovedSnapshot|reconcileOptimisticEntries)\b/,
         message: "timeline drag must not re-inline extracted optimistic or allocation finalize helper implementations",
       },
+      {
+        pattern: /\bfunction (?:isAllocationMultiSelected|startAllocationMultiDrag|updateAllocationMultiDrag|finalizeAllocationMultiDrag)\b/,
+        message: "timeline drag must not re-inline extracted allocation multi-drag helper implementations",
+      },
     ],
   },
   {