docs(web): MCP server on the landing page and in the manual

[tomasz-zajac-oss]

Summary

Adds the local MCP server (apps/mcp, #111) to the public site.

Landing page (apps/web/index.html)

• New Connect your agent section (#mcp) before "Run it locally". It has a short description, the build and claude mcp add commands, and links to the manual and to apps/mcp.
• New MCP server entry in "Also in the box".
• The "Modelled by either" tile now says "connect your agent over MCP" instead of "let an agent edit the .radical file", because the server works on Markdown folders only.

Manual (apps/web/manual.html)

• New MCP server section under Extend, covering:
  • what the server is
  • build steps and registration in Claude Code and Codex
  • the claude_desktop_config.json entry, with the full path to node
  • working alongside Studio: open the same folder, Studio reloads outside changes, and a tip to stay in Viewer while the agent writes
  • the tools grouped in a table
  • validation, placement, …-custom metamodel copies, and what is not supported
• Links to the new section from AI assistant, File formats and VS Code & local install, which now also lists npm run build -w @radical/mcp. The meta description and the intro now mention MCP.

Test plan

• Rendered both pages in headless Chromium at 1280 px and 390 px. No horizontal page scroll. Long command lines scroll inside the code block on phones.
• Checked the docs against the code: the folder watcher works in desktop and Chromium, and the query language includes LIST NODES WHERE, GET NEIGHBORS and LIST SEQUENCES.

🤖 Generated with Claude Code