feat(allocations): Sprint 2a — bulk date shift via BatchActionBar

Add "Shift Dates…" action to the batch action bar. Opens a modal with a
signed integer input; on confirm calls the existing timeline.batchShiftAllocations
procedure (allocationIds, daysDelta, mode="move").

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

apps/web/src/components/allocations/AllocationsClient.tsx

@@ -24,6 +24,7 @@ import { getPlanningEntryMutationId } from "~/lib/planningEntryIds.js";
 import { ALLOCATION_STATUS_BADGE as STATUS_BADGE } from "~/lib/status-styles.js";
 import { SuccessToast } from "~/components/ui/SuccessToast.js";
 import { EmptyState } from "~/components/ui/EmptyState.js";
+import { BatchDateShiftModal } from "./BatchDateShiftModal.js";
 import {
   collapseAllAllocationGroups,
   createInitialCollapsedAllocationGroups,
@@ -114,6 +115,7 @@ export function AllocationsClient() {
   const [batchStatusPicker, setBatchStatusPicker] = useState(false);
   const [confirmBatchStatus, setConfirmBatchStatus] = useState<{ ids: string[]; status: string } | null>(null);
   const [showStatusToast, setShowStatusToast] = useState(false);
+  const [showDateShiftModal, setShowDateShiftModal] = useState(false);
 
   const selection = useSelection();
   const utils = trpc.useUtils();
@@ -175,6 +177,15 @@ export function AllocationsClient() {
     },
   });
 
+  const batchDateShiftMutation = trpc.timeline.batchShiftAllocations.useMutation({
+    onSuccess: async () => {
+      await utils.allocation.list.invalidate();
+      await utils.allocation.listView.invalidate();
+      selection.clear();
+      setShowDateShiftModal(false);
+    },
+  });
+
   useEffect(() => {
     selection.clear();
   // eslint-disable-next-line react-hooks/exhaustive-deps
@@ -1024,6 +1035,11 @@ export function AllocationsClient() {
             onClick: () => setBatchStatusPicker(true),
             disabled: batchStatusMutation.isPending,
           },
+          {
+            label: "Shift Dates…",
+            onClick: () => setShowDateShiftModal(true),
+            disabled: batchDateShiftMutation.isPending,
+          },
           {
             label: `Delete (${selection.count})`,
             variant: "danger",
@@ -1033,6 +1049,18 @@ export function AllocationsClient() {
         ]}
       />
 
+      {/* Batch date shift modal */}
+      {showDateShiftModal && (
+        <BatchDateShiftModal
+          count={selection.count}
+          isPending={batchDateShiftMutation.isPending}
+          onConfirm={(daysDelta) =>
+            batchDateShiftMutation.mutate({ allocationIds: selectedMutationIds, daysDelta, mode: "move" })
+          }
+          onClose={() => setShowDateShiftModal(false)}
+        />
+      )}
+
       {/* Modal */}
       {modalOpen && (
         <AllocationModal allocation={editingAllocation} onClose={closeModal} onSuccess={closeModal} />