add json format

See merge request !2

Display detailed module information including:
- name, status, path, config path, line number
- availability status
- errors from config check

Supports --format=json output.

🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

- Add DeferredInfo struct for JSON serialization
- Add JSON output support to deferred info command

- Add JSON output support to preset info command
- Update ShowProfilesInfo to accept jsonFormat parameter

- Add --format flag to var list/info, module info, plugin list/info
- Support JSON output for all info/list commands

- Add config/format.go with FormatFlag and IsJSON helper
- Add ui/json.go with JSONItem struct and PrintJSON utility