Feature hasn't been suggested before.

• I have verified this feature I'm about to request hasn't been suggested before.

Describe the enhancement you want to request

Currently, the @-mention autocomplete only searches within the directory opencode was started in. There is no way to reference files outside that directory. Typing ~/ or an absolute path after @ returns no results.

It would be useful to support ~/ and absolute paths in @-mention autocomplete, listing directory contents and allowing file selection anywhere on the filesystem.