feat: vault-aligned server v1 + UX polish

Redesign the optional FastAPI companion around vault files (manifest /
PUT/GET/DELETE + OCR jobs) instead of legacy strokes_json notes. Wire a
client Server settings panel for health/login. Polish shell UX: l10n for
settings/home/board, sticky-board empty state, and a narrow-screen
diagnostics FAB.

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

server/tests/conftest.py

@@ -14,6 +14,7 @@ sys.path.insert(0, os.path.join(os.path.dirname(__file__), ".."))
 
 os.environ["BADNOTE_STORAGE_PATH"] = "/tmp/badnote_test_storage"
 os.environ["BADNOTE_QUEUE_PATH"] = "/tmp/badnote_test_queue"
+os.environ["BADNOTE_VAULT_PATH"] = "/tmp/badnote_test_vaults"
 os.environ["BADNOTE_JWT_SECRET"] = "test-secret-key-for-testing-only"
 
 from badnote_server.config import settings  # noqa: E402
@@ -26,10 +27,13 @@ async def setup_db(tmp_path):
     """Fresh DB and clean queue for each test."""
     db_path = str(tmp_path / "test.db")
     settings.db_path = db_path
+    settings.vault_path = str(tmp_path / "vaults")
     # Clean the queue directory before each test
     queue_path = settings.queue_path
     if os.path.exists(queue_path):
         shutil.rmtree(queue_path)
+    if os.path.exists(settings.vault_path):
+        shutil.rmtree(settings.vault_path)
     await init_db()
     yield
     await close_db()