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).

integrations/n8n-nodes-mem0/nodes/Mem0/Mem0.node.json

@@ -0,0 +1,21 @@
+{
+	"node": "n8n-nodes-mem0.mem0",
+	"nodeVersion": "1.0",
+	"codexVersion": "1.0",
+	"categories": ["AI"],
+	"subcategories": {
+		"AI": ["Memory"]
+	},
+	"resources": {
+		"primaryDocumentation": [
+			{
+				"url": "https://docs.mem0.ai/integrations/n8n"
+			}
+		],
+		"credentialDocumentation": [
+			{
+				"url": "https://docs.mem0.ai/integrations/n8n"
+			}
+		]
+	}
+}