Follow-up to #32053. The OAuth-over-SSH guide and the MCP feature page
previously only covered xAI and Spotify. Now that MCP servers can complete
OAuth via stdin paste-back on remote/headless hosts, document it.
oauth-over-ssh.md:
- Add MCP servers to the 'Which Providers Need This' table.
- New 'MCP Servers' section covering: paste-back (no setup, works
anywhere), SSH port forward (same pattern as xAI/Spotify), and the 30s
config-auto-reload race pitfall (use 'hermes mcp login <server>' from a
fresh terminal instead of editing config from inside a running session).
mcp.md:
- New 'OAuth-authenticated HTTP servers' section under HTTP servers,
covering auth: oauth config, token cache path, paste-back vs SSH
tunnel for headless hosts, and the same reload-race pitfall.
- Cross-links to the OAuth-over-SSH guide anchor.