chore(n8n): publish under the scoped @mem0/n8n-nodes-mem0 name

The unscoped `n8n-nodes-mem0` name is already taken on npm by an
unrelated publisher, so the CD workflow could never publish it. Move to
the `@mem0` scope, matching `@mem0/pi-agent-plugin` and
`@mem0/openclaw-mem0`, and add `publishConfig.access: public` since
scoped packages default to restricted.

n8n accepts scoped community packages: it strips the scope before
enforcing the `n8n-nodes-` prefix, the same shape as n8n's own
`@n8n/n8n-nodes-langchain`. Verified end to end on n8n 2.22.6 by
installing the packed tarball into the community-packages directory and
executing a workflow against node type `@mem0/n8n-nodes-mem0.mem0`.

The directory, workflow filenames, and the `n8n-nodes-mem0-v*` tag
prefix are unchanged. pnpm-lock.yaml needs no update: the pnpm v9 root
importer is anonymous and never recorded the package name.

integrations/n8n-nodes-mem0/README.md

@@ -1,4 +1,4 @@
-# n8n-nodes-mem0
+# @mem0/n8n-nodes-mem0
 
 This is an n8n community node that lets you use [Mem0](https://mem0.ai) — the memory layer for AI agents — in your n8n workflows.
 
@@ -10,7 +10,7 @@ Mem0 gives your agents long-term memory: add memories from conversations, then s
 
 ## Installation
 
-Follow the [community nodes installation guide](https://docs.n8n.io/integrations/community-nodes/installation/) and install `n8n-nodes-mem0`.
+Follow the [community nodes installation guide](https://docs.n8n.io/integrations/community-nodes/installation/) and install `@mem0/n8n-nodes-mem0`.
 
 ## Operations