Import: ThoughtSync-native round-trip + Google Keep Takeout

Complete the export/import pair (task 1907). POST /api/notes/import takes
an uploaded .zip and appends its notes — never overwriting existing ones.

Two formats, auto-detected:
- ThoughtSync export: recognized by its notes.json (app == thoughtsync);
  round-trips title/body/color/kind/pinned/archived/remind_at/timestamps/
  labels/items and re-attaches image media from the zip.
- Google Keep Takeout: each Keep <note>.json → a note. Maps title,
  textContent/listContent (+ checked), labels, Keep color enum (nearest
  palette match), isPinned/isArchived, isTrashed (→ trash), created/edited
  microsecond timestamps; folds annotation URLs into the body; resolves
  attachment filePaths relative to the note's folder.

Imported notes reuse create_note's derivation + reconciliation:
display-title derive, #tag reconcile, [[wiki-link]] rewrite. Explicit
labels attach as manual (via_tag=false); inline #tags reconcile as tags.
Image attachments copied into media storage; non-image types (e.g. Keep
audio) skipped until any-file attachments land.

Frontend: an Import control in the sidebar (next to Export) — hidden file
input + FormData POST + result toast ("Imported N notes (M skipped)"),
reloading the board + labels. New upload icon; notes-store importNotes().

Tests: import auth-guard + pure-helper coverage (_usec_to_dt, _keep_spec
list/text/color/annotation/attachment mapping, _native_spec round-trip).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FRgehjoz7Yv8LkUfADxACm

frontend/src/stores/notes.ts

@@ -171,6 +171,23 @@ export const useNotesStore = defineStore("notes", () => {
     reconcile(await api.del<Note>(`/api/notes/${id}/attachments/${attId}`));
   }
 
+  async function importNotes(file: File): Promise<{ source: string; imported: number; skipped: number }> {
+    const form = new FormData();
+    form.append("file", file);
+    const resp = await fetch("/api/notes/import", { method: "POST", credentials: "include", body: form });
+    const data: unknown = await resp.json().catch(() => ({}));
+    if (!resp.ok) {
+      const message =
+        typeof data === "object" && data !== null && "error" in data
+          ? String((data as { error: unknown }).error)
+          : "Import failed.";
+      throw { error: message, status: resp.status };
+    }
+    // Refresh the current lens so imported notes appear (labels reloaded by caller).
+    await load(view.value, activeLabel.value);
+    return data as { source: string; imported: number; skipped: number };
+  }
+
   async function fetchOne(id: string): Promise<Note | null> {
     try {
       return await api.get<Note>(`/api/notes/${id}`);
@@ -242,6 +259,7 @@ export const useNotesStore = defineStore("notes", () => {
     deleteItem,
     uploadAttachment,
     deleteAttachment,
+    importNotes,
     fetchOne,
     createTitled,
     reorder,