refine(skills): meta-convert-guide - fix naming (invalid focus)

## Summary

`meta-convert-guide` uses an invalid focus suffix 'guide' which is not in the allowed list.

## Current Name Analysis

- **Name**: meta-convert-guide
- **Segments**: 3
- **Focus**: guide ✗ (not in: ops, dev, eng, nub, xec)
- **Issue**: Invalid focus suffix

## Refinement Checklist

- [ ] Determine appropriate focus for this skill
- [ ] Option A: Rename to `meta-convert-authoring-dev` (development focus)
- [ ] Option B: Rename to `meta-convert-patterns-eng` (engineering focus)
- [ ] Option C: Add 'guide' to valid focus list (requires justfile update)
- [ ] If renaming, update skill directory name
- [ ] If renaming, update SKILL.md frontmatter
- [ ] Run `just validate-skill components/skills/` to verify
- [ ] Update any references to this skill in other files

## Allowed Focus Values

- `ops` - Operations/SRE focus
- `dev` - Development focus
- `eng` - Engineering/Architecture focus
- `nub` - Newcomer/beginner focus
- `xec` - Executive/management focus

## Validation Command

```bash
just validate-skill components/skills/meta-convert-guide
```