fix(collab): note attachments added or removed on the phone show in the Files tab at once

On the phone, attaching a file to a note, detaching one or deleting a
note with attachments left the trip's Files tab on the old list until a
reload. The desktop panel fires the local collab-files-changed event
that useTripWebSocket listens for, because the server leaves the
writer's own socket out of its broadcast; the phone notes tab never
fired it.

The event now lives in the shared useCollabNotesData hook:
uploadNoteFiles announces it once after a batch, and
announceNoteFilesChanged is what both shells call after deleting a note
or a note file. The desktop no longer fires it by hand after an upload.

Red before the fix: tests/unit/mobile/trip/MCollabNotes.test.tsx
FE-MOB-CNOTE-034 failed with "expected 0 to be 1" on the event count
after detaching a file. FE-COLLAB-NOTESDATA-009 covers the hook.
No existing assertions changed.

client/src/components/Collab/CollabNotes.tsx

@@ -16,7 +16,7 @@ import ConfirmDialog from '../shared/ConfirmDialog'
 import EmptyState from '../shared/EmptyState'
 import type { User } from '../../types'
 import type { CollabNote } from './CollabNotes.types'
-import { useCollabNotesData } from './useCollabNotesData'
+import { announceNoteFilesChanged, useCollabNotesData } from './useCollabNotesData'
 import { FONT, NOTE_COLORS } from './CollabNotes.constants'
 import { NoteFormModal } from './CollabNotesFormModal'
 import { CategorySettingsModal } from './CollabNotesCategorySettingsModal'
@@ -101,7 +101,6 @@ function useCollabNotes({ tripId, currentUser }: CollabNotesProps) {
         // Reload note with attachments
         const fresh = await collabApi.getNotes(tripId)
         if (fresh?.notes) setNotes(fresh.notes)
-        window.dispatchEvent(new Event('collab-files-changed'))
         return
       }
       setNotes(prev => {
@@ -185,13 +184,12 @@ function useCollabNotes({ tripId, currentUser }: CollabNotesProps) {
       await uploadNoteFiles(editingNote.id, pendingFiles)
       const fresh = await collabApi.getNotes(tripId)
       if (fresh?.notes) setNotes(fresh.notes)
-      window.dispatchEvent(new Event('collab-files-changed'))
     }
   }, [editingNote, tripId, handleUpdateNote, setNotes, uploadNoteFiles])
 
   const handleDeleteNoteFile = useCallback(async (noteId, fileId) => {
     try { await collabApi.deleteNoteFile(tripId, noteId, fileId) } catch { toast.error(t('common.error')) }
-    window.dispatchEvent(new Event('collab-files-changed'))
+    announceNoteFilesChanged()
   }, [tripId, toast, t])
 
   const handleDeleteNote = useCallback(async (noteId) => {
@@ -202,7 +200,7 @@ function useCollabNotes({ tripId, currentUser }: CollabNotesProps) {
       throw err
     }
     setNotes(prev => prev.filter(n => n.id !== noteId))
-    window.dispatchEvent(new Event('collab-files-changed'))
+    announceNoteFilesChanged()
   }, [tripId, toast, t, setNotes])
 
   // ── Derived data ──

client/src/components/Collab/useCollabNotesData.test.ts

@@ -1,4 +1,4 @@
-// FE-COLLAB-NOTESDATA-001 to FE-COLLAB-NOTESDATA-008: the note list behind the desktop
+// FE-COLLAB-NOTESDATA-001 to FE-COLLAB-NOTESDATA-009: the note list behind the desktop
 // Collab panel (empties on a failed load, waits for a trip id) and the phone's notes tab
 // (keeps the list, always loads), with
 // the live note events and the attachment upload both run after saving a note.
@@ -170,4 +170,23 @@ describe('useCollabNotesData', () => {
     act(() => result.current.setNotes([note(9)]));
     expect(result.current.notes.map((n) => n.id)).toEqual([9]);
   });
+
+  it('FE-COLLAB-NOTESDATA-009: an upload batch tells the Files tab to reload once, an empty one does not', async () => {
+    const onFilesChanged = vi.fn();
+    window.addEventListener('collab-files-changed', onFilesChanged);
+    try {
+      vi.mocked(collabApi.uploadNoteFile).mockRejectedValueOnce(new Error('too big'));
+      const { result } = await loaded();
+      await act(async () => {
+        await result.current.uploadNoteFiles(5, []);
+      });
+      expect(onFilesChanged).not.toHaveBeenCalled();
+      await act(async () => {
+        await result.current.uploadNoteFiles(5, [new File(['a'], 'a.pdf'), new File(['b'], 'b.pdf')]);
+      });
+      expect(onFilesChanged).toHaveBeenCalledTimes(1);
+    } finally {
+      window.removeEventListener('collab-files-changed', onFilesChanged);
+    }
+  });
 });

client/src/components/Collab/useCollabNotesData.ts

@@ -16,6 +16,15 @@ export interface CollabNotesDataOptions {
   waitForTripId?: boolean;
 }
 
+/**
+ * Tells the trip's Files tab that note attachments changed. The server leaves the writer's
+ * own socket out of its broadcast, so the tab that made the change has to say it itself;
+ * useTripWebSocket listens and reloads the files.
+ */
+export function announceNoteFilesChanged(): void {
+  window.dispatchEvent(new Event('collab-files-changed'));
+}
+
 /**
  * The trip notes behind the desktop Collab panel and the phone's notes tab, each reading
  * the rows through its own note type: the list as the server has it, kept current by the
@@ -76,7 +85,8 @@ export function useCollabNotesData<N extends { id: number } = CollabNoteData>({
 
   /**
    * Uploads a saved note's attachments one by one; a file the server refuses is toasted
-   * and the rest still go. `onFileError` sees each refusal before the toast.
+   * and the rest still go. `onFileError` sees each refusal before the toast. Once the
+   * batch is through, the Files tab is told to reload.
    */
   const uploadNoteFiles = useCallback(
     async (noteId: number, files: File[], onFileError?: (err: unknown) => void) => {
@@ -90,6 +100,7 @@ export function useCollabNotesData<N extends { id: number } = CollabNoteData>({
           toast.error(t('common.error'));
         }
       }
+      if (files.length > 0) announceNoteFilesChanged();
     },
     [tripId, toast, t]
   );

client/src/mobile/screens/trip/tabs/MCollabNotes.tsx

@@ -6,7 +6,7 @@ import { sanitizedMarkdownPlugins, sanitizedMarkdownComponents } from '../../../
 import { Check, ExternalLink, FileText, Paperclip, Pin, PinOff, Plus, StickyNote, Trash2, X } from 'lucide-react'
 import MDancingTrek from '../../../components/MDancingTrek'
 import { collabApi } from '../../../../api/client'
-import { useCollabNotesData } from '../../../../components/Collab/useCollabNotesData'
+import { announceNoteFilesChanged, useCollabNotesData } from '../../../../components/Collab/useCollabNotesData'
 import { openFile } from '../../../../utils/fileDownload'
 import { safeExternalHref } from '../../../../utils/safeUrl'
 import MSheet from '../../../components/MSheet'
@@ -115,6 +115,7 @@ export default function MCollabNotes({ planner }: MCollabNotesProps) {
     try {
       await collabApi.deleteNote(tripId, noteId)
       setNotes(prev => prev.filter(n => n.id !== noteId))
+      announceNoteFilesChanged()
     } catch {
       toast.error(t('common.error'))
     }
@@ -128,6 +129,7 @@ export default function MCollabNotes({ planner }: MCollabNotesProps) {
       setNotes(prev => prev.map(n => (
         n.id === noteId ? { ...n, attachments: n.attachments.filter(f => f.id !== fileId) } : n
       )))
+      announceNoteFilesChanged()
       return true
     } catch {
       toast.error(t('common.error'))

client/tests/unit/mobile/trip/MCollabNotes.test.tsx

@@ -607,4 +607,35 @@ describe('MCollabNotes', () => {
     expect(links).toHaveLength(1)
     expect(links[0]).toHaveAttribute('href', 'https://visa.test')
   })
+
+  it('FE-MOB-CNOTE-034: attaching, detaching and deleting tell the Files tab to reload', async () => {
+    let filesChanged = 0
+    const onFilesChanged = () => { filesChanged += 1 }
+    window.addEventListener('collab-files-changed', onFilesChanged)
+    try {
+      serveNotes([note(1, {
+        title: 'Visa',
+        attachments: [{ id: 5, filename: 'p', original_name: 'passport.pdf', url: '/uploads/p' }],
+      })])
+      serveWrites()
+      await renderNotes()
+
+      fireEvent.click(screen.getByText('Visa'))
+      fireEvent.click(within(screen.getByText('passport.pdf')).getByRole('button'))
+      await waitFor(() => expect(deletedFiles).toEqual(['1/5']))
+      await waitFor(() => expect(filesChanged).toBe(1))
+
+      fireEvent.change(fileInput(), { target: { files: [new File(['a'], 'x.pdf')] } })
+      fireEvent.click(screen.getByRole('button', { name: 'collab.notes.save' }))
+      await waitFor(() => expect(uploadedTo).toEqual(['1']))
+      await waitFor(() => expect(filesChanged).toBe(2))
+
+      fireEvent.click(await screen.findByRole('button', { name: 'collab.notes.delete' }))
+      fireEvent.click(screen.getByRole('button', { name: 'common.delete' }))
+      await waitFor(() => expect(deletedIds).toEqual(['1']))
+      await waitFor(() => expect(filesChanged).toBe(3))
+    } finally {
+      window.removeEventListener('collab-files-changed', onFilesChanged)
+    }
+  })
 })