Custom agents for opencode.
This option can either be:
- An attribute set defining agents
- A path to a directory containing multiple agent files
If an attribute set is used, the attribute name becomes the agent filename,
and the value is either:
- Inline content as a string (creates
opencode/agents/<name>.md)
- A path to a file (creates
opencode/agents/<name>.md)
If a path is used, it is expected to contain agent files.
The directory is symlinked to $XDG_CONFIG_HOME/opencode/agents/.