Webview crashes with "TypeError: undefined is not an object (evaluating 'e.groups().length')"

Description

When running bcs-code config (which spawns opencode <server-script> to serve a Config UI), opencode's webview crashes immediately with:

TypeError: undefined is not an object (evaluating 'e.groups().length')
when@http://127.0.0.1:17640/assets/index-9uLHN3Df.js:1523:15901

Environment

• opencode version: 1.18.16
• OS: macOS (darwin)
• Browser: opencode webview (port 17640)

Steps to reproduce

1. Run opencode <path-to-bun-server-script> where the script starts an HTTP server that prints a URL to stdout
2. opencode opens a webview to the printed URL
3. Webview crashes with the above error

What works

• The HTTP server itself starts and works correctly — verified with curl (HTTP 200, API responses are valid)
• Opening the same URL in Safari/Chrome works perfectly

Stack trace (full)

TypeError: undefined is not an object (evaluating 'e.groups().length')
when@http://127.0.0.1:17640/assets/index-9uLHN3Df.js:1523:15901
@http://127.0.0.1:17640/assets/index-9uLHN3Df.js:2:15538
w5@http://127.0.0.1:17640/assets/index-9uLHN3Df.js:2:6841
Jh@http://127.0.0.1:17640/assets/index-9uLHN3Df.js:2:6598
M7@http://127.0.0.1:17640/assets/index-9uLHN3Df.js:2:5612
w5@http://127.0.0.1:17640/assets/index-9uLHN3Df.js:2:6841
Jh@http://127.0.0.1:17640/assets/index-9uLHN3Df.js:2:6598
E@http://127.0.0.1:17640/assets/index-9uLHN3Df.js:2:2111
q@http://127.0.0.1:17640/assets/index-9uLHN3Df.js:2:15566
At@http://127.0.0.1:17640/assets/index-9uLHN3Df.js:2:4069
...

The error suggests a regex .match() result is not checked for null before calling .groups().length on it, somewhere in opencode's Preact-based rendering pipeline.