Convert functionality does not respect optional metadata from unified format

[reteps]

In .rules I have this content:

<sql-conventions>
<!-- Description: SQL Conventions -->
<!-- AlwaysApply: false -->
<!-- Globs: **/*.sql,**/*.ts,**/*.tsx -->

# foo
</sql-conventions>

After running yarn vibe-rules convert unified vscode .rules, I have:

cat .github/instructions/sql-conventions.instructions.md
---
applyTo: "**"
---
# sql-conventions

<!-- Description: SQL Conventions -->
<!-- AlwaysApply: false -->
<!-- Globs: **/*.sql,**/*.ts,**/*.tsx -->

# foo

This is obviously incorrect.