feat(integrations): add n8n community node for Mem0

A programmatic n8n community node wrapping the hosted Mem0 v3 REST API:
add, search, get, get-many, update, delete, plus usableAsTool so the n8n
AI Agent can call it.

- Zero runtime dependencies (calls REST directly), TypeScript, ESLint clean —
  meets n8n verified-node requirements
- Add supports custom_instructions, custom_categories, includes, excludes,
  a client-side entity-id guard, and async event polling (itemIndex on errors)
- Anonymous opt-out telemetry (MEM0_TELEMETRY=false)
- Docs page + docs.json/llms.txt entry, ci-gate + release wiring, AGENTS.md rows
- Verified: tsc + ESLint + live E2E (add → search → get → delete) vs api.mem0.ai

Split out of #6057 per review (separate PRs per integration).

.github/workflows/release.yml

@@ -45,6 +45,7 @@ jobs:
             openclaw-v*)  workflow="openclaw-cd.yml" ;;
             opencode-v*)  workflow="opencode-plugin-cd.yml" ;;
             pi-agent-v*)  workflow="pi-agent-plugin-cd.yml" ;;
+            n8n-nodes-mem0-v*) workflow="n8n-nodes-mem0-cd.yml" ;;
             v*)           workflow="cd.yml" ;;
             *)
               echo "::error::Release tag '$TAG' does not match any known package prefix — nothing will be published. See the tag prefix table in AGENTS.md."