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/vault.ts

@@ -187,6 +187,101 @@ export async function addAttachmentToItem(
   await syncManifestAttachments(git, handle, itemId, item, `manifest: sync attachments for ${itemId}`);
 }
 
+// --- Trash operations ---
+
+export function listTrashed(manifest: Manifest): Array<[ItemId, ManifestEntry]> {
+  return Object.entries(manifest.items)
+    .filter(([, entry]) => entry.trashed_at != null)
+    .sort(([, a], [, b]) => (b.trashed_at ?? 0) - (a.trashed_at ?? 0));
+}
+
+export async function restoreItem(
+  git: GitHost,
+  handle: SessionHandle,
+  manifest: Manifest,
+  itemId: ItemId,
+): Promise<void> {
+  const item = await fetchAndDecryptItem(git, handle, itemId);
+  const now = Math.floor(Date.now() / 1000);
+  const restored: Item = { ...item, trashed_at: undefined, modified: now };
+  await encryptAndWriteItem(git, handle, itemId, restored, `restore: ${item.title}`);
+  manifest.items[itemId] = { ...manifest.items[itemId], trashed_at: undefined, modified: now };
+  await encryptAndWriteManifest(git, handle, manifest, `manifest: restore ${item.title}`);
+}
+
+export async function purgeItem(
+  git: GitHost,
+  itemId: ItemId,
+  manifest: Manifest,
+): Promise<string[]> {
+  const entry = manifest.items[itemId];
+  const deletedBlobs: string[] = [];
+
+  // Delete attachments
+  for (const att of entry?.attachment_summaries ?? []) {
+    try {
+      await git.deleteBlob(`attachments/${att.id}.bin`, `purge attachment: ${att.filename}`);
+      deletedBlobs.push(att.id);
+    } catch { /* blob may not exist */ }
+  }
+
+  // Delete item file
+  await git.deleteFile(`items/${itemId}.enc`, `purge: ${entry?.title ?? itemId}`);
+
+  // Update manifest
+  delete manifest.items[itemId];
+
+  return deletedBlobs;
+}
+
+export async function purgeAllTrash(
+  git: GitHost,
+  handle: SessionHandle,
+  manifest: Manifest,
+): Promise<{ itemCount: number; orphanCount: number }> {
+  const trashed = listTrashed(manifest);
+  const allDeletedBlobs = new Set<string>();
+
+  // Purge each trashed item
+  for (const [id] of trashed) {
+    const deleted = await purgeItem(git, id, manifest);
+    deleted.forEach((b) => allDeletedBlobs.add(b));
+  }
+
+  // Collect all referenced attachment IDs from remaining items
+  const referenced = new Set<string>();
+  for (const entry of Object.values(manifest.items)) {
+    for (const att of entry.attachment_summaries ?? []) {
+      referenced.add(att.id);
+    }
+  }
+
+  // Scan for orphan blobs
+  let orphanCount = 0;
+  try {
+    const blobFiles = await git.listDir('attachments');
+    for (const filename of blobFiles) {
+      const id = filename.replace(/\.bin$/, '');
+      if (!referenced.has(id) && !allDeletedBlobs.has(id)) {
+        try {
+          await git.deleteBlob(`attachments/${filename}`, `purge orphan: ${id}`);
+          orphanCount++;
+        } catch { /* ignore */ }
+      }
+    }
+  } catch { /* attachments dir may not exist */ }
+
+  // Write manifest once
+  if (trashed.length > 0 || orphanCount > 0) {
+    await encryptAndWriteManifest(
+      git, handle, manifest,
+      `trash: purge ${trashed.length} items + ${orphanCount} orphan blobs`,
+    );
+  }
+
+  return { itemCount: trashed.length, orphanCount };
+}
+
 /// Remove attachments matching the given IDs from the item.
 /// Returns the removed AttachmentRefs (so the caller can deleteBlob the
 /// underlying bytes). IDs not present in the item's attachments are