fix(integrations): address review feedback on Zapier and n8n

Zapier:
- Bound the poll budget under Zapier's step timeout and default Wait for
  Completion off; timeout message notes the add likely still succeeded
- Add offline unit tests (mocked z.request) and run them in CI
- Expose a Page input on Get Memories
- Encode memory_id in the delete path
- Update E2E to test the default no-wait path (add then search-retry)

n8n:
- Clarify the Infer description (controls extraction, not waiting)
- Add an App ID field and require at least one entity id before add
- Pass itemIndex into pollEvent errors
- Unwrap event results so wait-path output matches search and get many

integrations/zapier-mem0/searches/get_memories.js

@@ -7,7 +7,10 @@ const perform = async (z, bundle) => {
 	const response = await z.request({
 		url: '/v3/memories/',
 		method: 'POST',
-		params: { page: 1, page_size: Math.max(1, Math.floor(Number(bundle.inputData.limit) || 50)) },
+		params: {
+			page: Math.max(1, Math.floor(Number(bundle.inputData.page) || 1)),
+			page_size: Math.max(1, Math.floor(Number(bundle.inputData.limit) || 50)),
+		},
 		body,
 	});
 	const data = response.data;
@@ -25,7 +28,20 @@ module.exports = {
 		perform,
 		inputFields: [
 			{ key: 'user_id', label: 'User ID', type: 'string', required: true },
-			{ key: 'limit', label: 'Limit', type: 'integer', default: '50' },
+			{
+				key: 'limit',
+				label: 'Limit',
+				type: 'integer',
+				default: '50',
+				helpText: 'Max memories per page. Use Page to page through larger result sets.',
+			},
+			{
+				key: 'page',
+				label: 'Page',
+				type: 'integer',
+				default: '1',
+				helpText: 'Which page of results to return (1-based).',
+			},
 		],
 		sample: { id: '00000000-0000-0000-0000-000000000000', memory: 'User loves hiking' },
 	},