fix: update test assertion for new key escaping format

The MappingKey::escape_project now replaces / with :: so
'issue:g/p:42' becomes 'issue:g::p:42'.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

tests/mocks/tauri-api.ts

@@ -39,6 +39,11 @@ export const invoke = vi.fn(async (cmd: string, _args?: unknown) => {
       return { created: 0, closed: 0, skipped: 0, healed: 0, errors: [] };
     case "quick_capture":
       return { bead_id: "bd-mock-capture" };
+    case "read_state":
+      return null;
+    case "write_state":
+    case "clear_state":
+      return null;
     default:
       throw new Error(`Mock not implemented for command: ${cmd}`);
   }