fix(n8n): escape ids in URLs, add agent/run filters, run tests in CI

Three review findings on the Mem0 n8n node:

- Memory IDs and event IDs were interpolated raw into request paths, so a
  value containing / or .. could reach a different endpoint than intended.
  Wrap all four sites in encodeURIComponent.

- Search and Get Many could only filter by user_id, leaving agent- and
  run-scoped memories unreachable from the node. Both now accept User ID,
  Agent ID, and Run ID. Multiple ids combine with OR because Mem0 indexes
  entities separately and an AND across them matches nothing. User ID is
  no longer marked required; the node still fails with a clear message
  when all three are empty, rather than letting the API return a raw 400.

- n8n-nodes-mem0-checks.yml ran lint and build but never the jest suite,
  so the tests could rot unnoticed. Add a test job matching the layout of
  pi-agent-plugin-checks.yml.

Tests cover flat single-entity filters, the OR combination, agent-only
listing, the empty-entity guard on both operations, and id escaping in
the get/delete/poll URLs. Docs and README document the new fields and the
OR semantics.

.github/workflows/n8n-nodes-mem0-checks.yml

@@ -35,6 +35,29 @@ jobs:
       - name: Lint
         run: cd integrations/n8n-nodes-mem0 && pnpm run lint
 
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install pnpm
+        uses: pnpm/action-setup@v4
+        with:
+          version: 9
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: 20
+          cache: 'pnpm'
+          cache-dependency-path: integrations/n8n-nodes-mem0/pnpm-lock.yaml
+
+      - name: Install dependencies
+        run: cd integrations/n8n-nodes-mem0 && pnpm install --frozen-lockfile --ignore-scripts
+
+      - name: Run tests
+        run: cd integrations/n8n-nodes-mem0 && pnpm test
+
   build:
     runs-on: ubuntu-latest
     steps: