Add opt-in MemCode Memory plugin

[vivekgupta-memcode]

Plugin

• Id: com.github.vivekgupta-memcode/memcode-memory
• Repository: https://github.com/vivekgupta-memcode/skales-memcode
• Version: 0.1.0 · minAppVersion: 12.9.45 (provisional; app test pending)
• Class: page
• Platforms: desktop

What it does, in one sentence: Lets a signed-in user explicitly save, check, search and recall personal MemCode memories from a Skales plugin page.

Why it needs the permissions it declares: The four named MCP tools call the user-configured MemCode remote server. It has no file or Skales shared-memory access. The user connects https://mcp.memcode.in/mcp as server memcode and signs in via Skales' OAuth flow; the page never receives a key or token.

Following skalesapp/skales#312, this adds an optional plugin, leaving Skales' local memory as it is. Nothing reads chat history or uploads data automatically. Saves happen only on the user's button press. MemCode is freemium, as disclosed in the manifest.

Checklist

• The plugin lives in a public GitHub repository I own.
• The repository has a plugin.json at the submitted path, and it validates against schema/plugin.schema.json.
• The id is com.github.<owner>/<slug>, with the owner spelled exactly as the GitHub repository owner.
• The id is new and does not appear in removed.json.
• The name does not use "Skales".
• version is semver and matches a tag or release; minAppVersion is a version I actually tested against. (Tag and app test pending.)
• description is one factual sentence, no marketing.
• class describes the plugin's main job.
• permissions is the smallest set that works. (Awaiting in-app MCP permission test.)
• No secrets in the repository, no telemetry, no code loaded and executed at runtime.
• If the plugin is paid or freemium, business says so.
• I commit to maintaining this plugin: keeping it working against current Skales releases, answering issues in my repository, and telling you when I stop.
• This PR adds exactly one entry, at the end of plugins.json, and touches nothing else.
• node scripts/validate.js passes locally. (11 entries, 10 featured, 0 retired ids.)