fix(n8n): distinct light/dark icon files (0.1.4)

0.1.3 failed vetting on @n8n/community-nodes/icon-validation: light and dark
icon variants must be DIFFERENT files, but both pointed at mem0.svg. Add a
distinct light-theme variant (mem0-light.svg, brand purple #8F74E0 — the
existing mem0.svg is white and only reads on dark backgrounds) and wire
icon = { light: 'file:mem0-light.svg', dark: 'file:mem0.svg' } on both the
node and the credential. Verified locally: both icon-validation and
icon-prefer-themed-variants pass (0 problems). Matches the verified
@probo/n8n-nodes-probo pattern (probo-light.svg + probo.svg).

integrations/n8n-nodes-mem0/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@mem0/n8n-nodes-mem0",
-  "version": "0.1.3",
+  "version": "0.1.4",
   "description": "n8n community node for Mem0 — the memory layer for AI agents. Add, search, get, update, and delete long-term memories.",
   "keywords": [
     "n8n-community-node-package",