fix(n8n): address review feedback and pass the verification scanner

- Telemetry: replace client-side PostHog (which read process.env, banned in
  verified nodes) with first-party `source: "N8N"` attribution on API requests,
  mirroring OpenClaw. Removes the undisclosed-collection concern entirely.
- Verification-scanner fixes: add credential icon, use NodeConnectionTypes.Main
  instead of the 'main' literal, wrap error paths in NodeApiError, stop shipping
  .d.ts / tsbuildinfo, and align the local eslint config with the scanner.
- Add offline unit tests (jest): entity-id guard, JSON-parse errors, poll-timeout
  loop, source attribution, and Return All pagination.
- Get Many: add a Return All option that pages through all memories.
- Docs: README telemetry note and an AGENTS.md Key Directories row.

Verified: build + tsc + eslint + 5 unit tests + live E2E against api.mem0.ai, and
the packed tarball passes @n8n/scan-community-package with zero violations.

integrations/n8n-nodes-mem0/tsconfig.json

@@ -14,9 +14,10 @@
     "strictNullChecks": true,
     "preserveConstEnums": true,
     "esModuleInterop": true,
+    "isolatedModules": true,
     "resolveJsonModule": true,
-    "incremental": true,
-    "declaration": true,
+    "incremental": false,
+    "declaration": false,
     "sourceMap": true,
     "skipLibCheck": true,
     "outDir": "./dist/"