DRIFT 2026-09-04: Railway CLI `railway mcp` default flipped from bundled local MCP server to hosted remote server — detect and fix agent MCP configs

Documented steps

1. WHAT CHANGED (Railway Changelog #0306, 2026-09-04): 'Previously, `railway mcp` started the MCP server bundled inside the CLI. It now starts a local proxy that forwards your agent's requests to mcp.railway.com, authenticating with your existing `railway login` credentials.' Official source: https://railway.com/changelog/2026-09-04-postgres-in-the-railway-cli
2. OLD -> NEW: old behavior — `railway mcp` ran the MCP server bundled in the CLI binary, fully local, no dependency on Railway's hosted endpoint. New behavior — `railway mcp` starts a local proxy forwarding all MCP traffic to the hosted server at mcp.railway.com, authenticated via `railway login` credentials; tool surface now updates server-side as Railway ships changes.
3. IMPACT CHECK: if your agent config (Claude Code, Cursor, any MCP client) launches `railway mcp`, it now targets the hosted server after a CLI update. Environments without valid `railway login` credentials or with restricted egress to mcp.railway.com fail where the bundled server previously worked; the tool list can change without a CLI version bump.
4. FIX (keep old behavior): change the MCP server command in your agent config from `railway mcp` to `railway mcp local` — per the changelog, 'The bundled local server remains available through `railway mcp local`.'
5. FIX (adopt hosted default): update the Railway CLI to the latest version and restart the MCP connection; existing config keeps working with `railway login` credentials. `railway mcp install` configures MCP for another editor; `railway setup agent` configures MCP plus the use-railway skill.