refactor(web): extract project drag finalize

apps/web/src/hooks/useTimelineDrag.ts

@@ -24,7 +24,8 @@ import { finalizeAllocationReleaseEffects } from "./timelineAllocationReleaseEff
 import { cleanupTimelineDragState } from "./timelineDragCleanup.js";
 import { resolveAllocationDragPosition, resolveProjectDragPosition } from "./timelineDragPosition.js";
 import { attachDocumentMouseDrag } from "./timelineDocumentDrag.js";
-import { buildProjectShiftMutationInput, createProjectDragState } from "./timelineProjectDrag.js";
+import { finalizeProjectDrag } from "./timelineProjectDragFinalize.js";
+import { createProjectDragState } from "./timelineProjectDrag.js";
 import { beginProjectDragSession } from "./timelineProjectDragSession.js";
 import {
   forwardCanvasTouchEnd,
@@ -408,28 +409,18 @@ export function useTimelineDrag({
     mutateAsync: (...args: unknown[]) => Promise<unknown>;
   };
 
-  const finalizeProjectDrag = useCallback(
-    (clientX: number, mode: "mutate" | "mutateAsync" = "mutate") => {
-      updateProjectDragPosition(clientX);
-      const finalDrag = dragStateRef.current;
-      if (!finalDrag.isDragging) return null;
-
-      const mutationInput = buildProjectShiftMutationInput(finalDrag);
-
-      if (finalDrag.daysDelta !== 0) {
-        preserveLivePreview(projectPreviewRef.current);
-      }
-
-      clearProjectDragSession();
-
-      if (!mutationInput) return null;
-      if (mode === "mutateAsync") {
-        return applyShiftMutation.mutateAsync(mutationInput);
-      }
-
-      applyShiftMutation.mutate(mutationInput);
-      return null;
-    },
+  const finalizeActiveProjectDrag = useCallback(
+    (clientX: number, mode: "mutate" | "mutateAsync" = "mutate") =>
+      finalizeProjectDrag({
+        clientX,
+        mode,
+        dragRef: dragStateRef,
+        previewRef: projectPreviewRef,
+        updatePosition: updateProjectDragPosition,
+        clearSession: clearProjectDragSession,
+        mutate: applyShiftMutation.mutate,
+        mutateAsync: applyShiftMutation.mutateAsync,
+      }),
     [applyShiftMutation, clearProjectDragSession, updateProjectDragPosition],
   );
 
@@ -516,11 +507,11 @@ export function useTimelineDrag({
         attachDrag: attachDocumentMouseDrag,
         updatePosition: updateProjectDragPosition,
         finalize: (clientX) => {
-          void finalizeProjectDrag(clientX);
+          void finalizeActiveProjectDrag(clientX);
         },
       });
     },
-    [finalizeProjectDrag, setProjectPreviewTargets, updateProjectDragPosition],
+    [finalizeActiveProjectDrag, setProjectPreviewTargets, updateProjectDragPosition],
   );
 
   // Legacy — kept for backward compat (triggers project shift from allocation block)
@@ -717,7 +708,7 @@ export function useTimelineDrag({
       const drag = dragStateRef.current;
       if (drag.isDragging) {
         try {
-          await finalizeProjectDrag(e.clientX, "mutateAsync");
+          await finalizeActiveProjectDrag(e.clientX, "mutateAsync");
         } catch {
           // Validation error — revert visually
         }
@@ -734,7 +725,7 @@ export function useTimelineDrag({
         setRangeState(INITIAL_RANGE_STATE);
       }
     },
-    [finalizeProjectDrag, onRangeSelected],
+    [finalizeActiveProjectDrag, onRangeSelected],
   );
 
   const onCanvasMouseLeave = useCallback(() => {