fix(pi): serialize write-leased tool batches

tests/unit/pi-extension-bundle.test.ts

@@ -22,6 +22,7 @@ type ExtensionHandler = (...arguments_: unknown[]) => Promise<unknown> | unknown
 type ExtensionTool = {
   name: string;
   parameters?: Record<string, unknown>;
+  executionMode?: 'sequential';
   execute?: (...arguments_: unknown[]) => Promise<unknown>;
 };
 
@@ -213,6 +214,7 @@ describe('Makelore Pi extension bundle', () => {
       expect(tools.has('data_service_inspect')).toBe(true);
       expect(tools.has('data_service_put_document')).toBe(false);
       expect(tools.get('data_service_inspect')?.parameters).toEqual(pluginTool.inputSchema);
+      expect(tools.get('data_service_inspect')?.executionMode).toBe('sequential');
       const context = JSON.parse(await readFile(registration.env.MAKELORE_PI_CONTEXT_FILE as string, 'utf8'));
       expect(context).toMatchObject({
         catalogRevision: 19,