Fix #1685: the Basic auth header for the OpenCode server was hardcoded to use the username 'opencode', ignoring OPENCODE_SERVER_USERNAME. Users who set a custom username got 401 errors because the server expected a different credential. Both call sites (web server auth-state-runtime.js and VS Code extension opencode.ts) now read process.env.OPENCODE_SERVER_USERNAME with a fallback to 'opencode' to preserve prior behavior. Co-authored-by: Leonid Skorobogatyy <bash@opencode.itc.local>