feat(ext/sw): trash operations — listTrashed, restoreItem, purgeItem, purgeAllTrash

listTrashed filters manifest for trashed_at != null, sorted newest-first.
restoreItem clears trashed_at. purgeItem deletes item + attachments.
purgeAllTrash also scans for orphan blobs in attachments/ directory.

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

extension/src/service-worker/__tests__/trash.test.ts

@@ -0,0 +1,48 @@
+import { describe, expect, it } from 'vitest';
+import { listTrashed } from '../vault';
+import type { Manifest } from '../../shared/types';
+
+function makeManifest(items: Record<string, { trashed_at?: number }>): Manifest {
+  const manifest: Manifest = { schema_version: 2, items: {} };
+  for (const [id, { trashed_at }] of Object.entries(items)) {
+    manifest.items[id] = {
+      id,
+      type: 'login',
+      title: `Item ${id}`,
+      tags: [],
+      favorite: false,
+      modified: 1000,
+      trashed_at,
+      attachment_summaries: [],
+    };
+  }
+  return manifest;
+}
+
+describe('listTrashed', () => {
+  it('returns empty array when no trashed items', () => {
+    const manifest = makeManifest({ a: {}, b: {} });
+    expect(listTrashed(manifest)).toEqual([]);
+  });
+
+  it('filters to only trashed items', () => {
+    const manifest = makeManifest({
+      a: {},
+      b: { trashed_at: 1000 },
+      c: { trashed_at: 2000 },
+    });
+    const result = listTrashed(manifest);
+    expect(result).toHaveLength(2);
+    expect(result.map(([id]) => id)).toEqual(['c', 'b']); // sorted newest first
+  });
+
+  it('sorts by trashed_at descending', () => {
+    const manifest = makeManifest({
+      old: { trashed_at: 100 },
+      mid: { trashed_at: 500 },
+      new: { trashed_at: 900 },
+    });
+    const result = listTrashed(manifest);
+    expect(result.map(([id]) => id)).toEqual(['new', 'mid', 'old']);
+  });
+});