feedback(meta-convert-dev): from convert-scala-fsharp creation

## Feedback: meta-convert-dev

### Context
- **Task**: Creating `convert-scala-fsharp` skill
- **Used for**: Foundation patterns, APTV workflow, type mapping strategies

### What Worked Well
- APTV workflow provided clear structure for the conversion process
- Type mapping tables were excellent templates to follow
- The concept of "adopt target idioms, don't transliterate" was crucial
- Examples from existing conversion skills (especially convert-fsharp-scala) were invaluable
- Paradigm translation section helped frame the JVM→.NET shift

### Suggested Improvements
- [ ] Add more guidance on handling platform-specific features (e.g., JVM stdlib → .NET BCL)
- [ ] Include patterns for converting between similar functional languages (functional→functional is not trivial)
- [ ] Add guidance on when to use units of measure vs single-case unions vs opaque types
- [ ] More examples of async/concurrency translations across different platforms

### Additional Notes
The reverse skill (convert-fsharp-scala) was extremely helpful as a reference. The symmetry between conversion skills is valuable.

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Feedback from: `/create-lang-conversion-skill scala fsharp`
Relates to #348, #344, #332