fix: Bug - Sending files and attachment issues

Hydrate playable media after disk receive, relay file-announce to sibling
devices via account_sync, bind DM attachments to pre-allocated message ids,
and improve gallery retry/cancel UX with bounded parallel auto-downloads.

Co-authored-by: Cursor <cursoragent@cursor.com>

toju-app/src/app/domains/direct-message/domain/rules/dm-message-send.rules.spec.ts

@@ -0,0 +1,30 @@
+import { planDmMessageSend } from './dm-message-send.rules';
+
+function makeFile(name: string): File {
+  return new File(['x'], name, { type: 'image/png' });
+}
+
+describe('planDmMessageSend', () => {
+  it('binds attachments to the same pre-allocated message id', () => {
+    const generateId = () => 'dm-msg-1';
+    const plan = planDmMessageSend({
+      generateId,
+      content: 'hello',
+      pendingFiles: [makeFile('a.png'), makeFile('b.png')]
+    });
+
+    expect(plan.action.id).toBe('dm-msg-1');
+    expect(plan.attachmentBinding?.messageId).toBe('dm-msg-1');
+    expect(plan.attachmentBinding?.files).toHaveLength(2);
+  });
+
+  it('returns no attachment binding when there are no pending files', () => {
+    const plan = planDmMessageSend({
+      generateId: () => 'dm-msg-2',
+      content: 'text only',
+      pendingFiles: []
+    });
+
+    expect(plan.attachmentBinding).toBeNull();
+  });
+});