Task #463: @dnd-kit notes drag + reorder

- Replace HTML5+touch drag with @dnd-kit; MouseSensor (desktop, 8px)
  + TouchSensor (iPad, 200ms long-press) so input sources never overlap.
- Add sort_order column; ORDER BY asc(sortOrder), updatedAt desc.
- PATCH /notes/reorder: strict isPinned boolean check, bucket+permission
  scoped, all writes wrapped in db.transaction for atomicity.
- PATCH /notes/:id stamps sort_order = min-1 on folder/pin bucket change.
- Client useReorderNotes (PATCH) with optimistic cache update.
- handleDragEnd builds reorder payload from FULL bucket (owner notes
  or shared-folder bucket via ref), not the filtered subset, so hidden
  siblings under search/label filters keep their order.
- Drag guarded for view-only contexts: source must be owned OR in
  editable shared bucket; folder-drop additionally requires isOwn.
- SharedFolderView publishes its data.notes via bucketRef when viewer
  has edit permission, enabling correct reorder in shared folders.
- Layout fix at narrow viewport: rail stacks above notes
  (flex-col md:flex-row) so iPad portrait drag has proper bbox.
- Playwright tests: notes-folders.spec.mjs both desktop pointer drag
  and touch long-press drag pass (33s).
- OpenAPI codegen skipped: notes-api.ts is hand-written.
- Out of scope (pre-existing failures): executive-meetings reorder/font,
  notes-share PATCH 403/404, groups-crud rollback.

artifacts/tx-os/src/lib/notes-api.ts

@@ -588,7 +588,7 @@ export function useReorderNotes() {
       orderedIds: number[];
     }) =>
       req<{ success: true; updated: number }>(`/notes/reorder`, {
-        method: "POST",
+        method: "PATCH",
         body: JSON.stringify({ folderId, isPinned, orderedIds }),
       }),
     onMutate: async ({ folderId, isPinned, orderedIds }) => {

artifacts/tx-os/src/pages/notes.tsx

@@ -114,7 +114,7 @@ import {
 } from "@/components/notes/folders-rail";
 import {
   DndContext,
-  PointerSensor,
+  MouseSensor,
   TouchSensor,
   useSensor,
   useSensors,
@@ -221,21 +221,19 @@ export default function NotesPage() {
   const reorderNotes = useReorderNotes();
   const showFolders = view === "active" || view === "archived";
 
-  // SharedFolderView publishes its currently visible notes here so that
-  // the page-level handleDragEnd can build a reorder payload from the
-  // shared-folder bucket (the page's own `notes` array doesn't include
-  // notes belonging to folders shared by other users).
+  // SharedFolderView publishes its visible notes here only when the
+  // viewer has edit permission, so handleDragEnd can resolve the bucket
+  // for shared folders. Null means "no editable shared-folder context".
   const sharedFolderBucketRef = useRef<{
     folderId: number;
     notes: Note[];
   } | null>(null);
 
-  // Sensors mirror the home.tsx pattern: a small pointer threshold so
-  // clicks/taps on the card body still fire onClick (open editor), and a
-  // 200ms long-press for touch with a generous tolerance so iPad scroll
-  // gestures don't accidentally start a drag.
+  // MouseSensor for desktop (8px threshold so clicks still open the editor)
+  // and TouchSensor for iPad with a 200ms long-press, kept on separate input
+  // sources so touch can never activate before the long-press elapses.
   const sensors = useSensors(
-    useSensor(PointerSensor, { activationConstraint: { distance: 8 } }),
+    useSensor(MouseSensor, { activationConstraint: { distance: 8 } }),
     useSensor(TouchSensor, {
       activationConstraint: { delay: 200, tolerance: 8 },
     }),
@@ -326,7 +324,17 @@ export default function NotesPage() {
         | undefined;
       if (!a || a.type !== "note" || a.noteId == null) return;
 
+      // Only allow drag actions when the source note belongs to a context
+      // we can actually mutate: the user's own notes, or a shared folder
+      // they have edit permission on (published via sharedFolderBucketRef).
+      const sharedBucket = sharedFolderBucketRef.current;
+      const isOwn = notes.some((n) => n.id === a.noteId);
+      const isEditableShared =
+        !!sharedBucket && sharedBucket.notes.some((n) => n.id === a.noteId);
+      if (!isOwn && !isEditableShared) return;
+
       if (o?.type === "folder-drop" && o.target !== undefined) {
+        if (!isOwn) return;
         moveNoteToTarget(o.target, a.noteId);
         return;
       }
@@ -335,13 +343,8 @@ export default function NotesPage() {
         if (a.noteId === o.noteId) return;
         if (a.folderId !== o.folderId) return;
         if (a.isPinned !== o.isPinned) return;
-        // Build the bucket from the FULL underlying source for the active
-        // surface (owner notes vs shared-folder notes), not the filtered
-        // view. If we used the filtered subset, search/label filters would
-        // omit hidden siblings from `orderedIds` and the server would
-        // reassign sort_order=0..N-1 over only the visible rows, leaving
-        // duplicates against the hidden ones.
-        const sharedBucket = sharedFolderBucketRef.current;
+        // Use the FULL bucket source (not the filtered view) so search /
+        // label filters can't strand hidden siblings out of orderedIds.
         const sourceNotes =
           sharedBucket && sharedBucket.folderId === a.folderId
             ? sharedBucket.notes
@@ -3071,11 +3074,8 @@ function SharedFolderView({
   // Recipients use the same top-bar search input as their personal notes;
   // filter the read-only list client-side over title + content + checklist
   // item text so the experience matches the owner's view.
-  // Publish the FULL (unfiltered) shared-folder bucket to the page-level
-  // ref so handleDragEnd can build a correct reorder payload even when a
-  // search filter is active. We only publish when this viewer can edit
-  // (otherwise reorder is forbidden anyway). Cleared on unmount and when
-  // the folder switches.
+  // Publish the full bucket only for editors so handleDragEnd has a
+  // correct source. View-only viewers leave the ref null (drag disabled).
   useEffect(() => {
     if (!data || data.myPermission !== "edit") {
       bucketRef.current = null;