ci(integrations): add CI/CD workflows for n8n + Zapier packages

Match the repo's per-integration CI/CD convention (vercel-ai / pi-agent
pattern):

- n8n-nodes-mem0-checks.yml (lint + build + dist verify) and
  n8n-nodes-mem0-cd.yml (npm publish --provenance via OIDC, dispatched by
  the release router on tag n8n-nodes-mem0-v*).
- zapier-mem0-checks.yml (zapier validate) and zapier-mem0-cd.yml (manual
  zapier push; requires ZAPIER_DEPLOY_KEY). Zapier deploys to Zapier's
  platform, not npm, so it is not in the release router.
- Wire both packages into ci-gate.yml (path filters + call jobs + gate).
- Register the n8n tag prefix in release.yml and document it + the Zapier
  manual-deploy in AGENTS.md.
- Skip the Zapier E2E suite when MEM0_API_KEY is absent so CI is green
  offline (it still runs locally with a key).

.github/workflows/ci-gate.yml

@@ -40,6 +40,8 @@ jobs:
       openclaw: ${{ steps.filter.outputs.openclaw }}
       opencode_plugin: ${{ steps.filter.outputs.opencode_plugin }}
       pi_agent_plugin: ${{ steps.filter.outputs.pi_agent_plugin }}
+      n8n_nodes_mem0: ${{ steps.filter.outputs.n8n_nodes_mem0 }}
+      zapier_mem0: ${{ steps.filter.outputs.zapier_mem0 }}
       docs_llms_txt: ${{ steps.filter.outputs.docs_llms_txt }}
     steps:
       - uses: dorny/paths-filter@v3
@@ -79,6 +81,14 @@ jobs:
               - 'integrations/pi-agent-plugin/**'
               - '.github/workflows/pi-agent-plugin-checks.yml'
               - '.github/workflows/ci-gate.yml'
+            n8n_nodes_mem0:
+              - 'integrations/n8n-nodes-mem0/**'
+              - '.github/workflows/n8n-nodes-mem0-checks.yml'
+              - '.github/workflows/ci-gate.yml'
+            zapier_mem0:
+              - 'integrations/zapier-mem0/**'
+              - '.github/workflows/zapier-mem0-checks.yml'
+              - '.github/workflows/ci-gate.yml'
             docs_llms_txt:
               - 'docs/**/*.mdx'
               - 'docs/llms.txt'
@@ -136,6 +146,20 @@ jobs:
     uses: ./.github/workflows/pi-agent-plugin-checks.yml
     secrets: inherit
 
+  n8n-nodes-mem0:
+    name: n8n node
+    needs: changes
+    if: needs.changes.outputs.n8n_nodes_mem0 == 'true'
+    uses: ./.github/workflows/n8n-nodes-mem0-checks.yml
+    secrets: inherit
+
+  zapier-mem0:
+    name: Zapier app
+    needs: changes
+    if: needs.changes.outputs.zapier_mem0 == 'true'
+    uses: ./.github/workflows/zapier-mem0-checks.yml
+    secrets: inherit
+
   docs-llms-txt:
     name: docs llms.txt
     needs: changes
@@ -154,6 +178,8 @@ jobs:
       - openclaw
       - opencode-plugin
       - pi-agent-plugin
+      - n8n-nodes-mem0
+      - zapier-mem0
       - docs-llms-txt
     if: always()
     runs-on: ubuntu-latest