fix(pm): convert inline backtick preflights to multiline bash blocks

[veinkr-bot]

Summary

Fixes a permission checker error that occurred when running pm skills with preflight commands containing quoted characters in flag values (e.g. --jq '...').

Changes

• Converted all inline backtick preflight syntax (!...``) to multiline !```bash blocks across all affected pm skills:
  • spec-abandon: 3 preflights converted
  • spec-status: 3 preflights converted
  • spec-next: 3 preflights converted
  • spec-init: 3 preflights converted
  • spec-list: 1 preflight converted
  • spec-decompose: 1 preflight converted
  • spec-plan: 1 preflight converted

Related Issues

Follows the bash block rule established in .claude/rules/skill-bash-blocks.md and the fix from #207.

Testing

• Tested locally
• Docker build/container works (if applicable)
• Manual testing completed

Checklist

• Code follows project conventions (shell script style, Python formatting)
• Documentation updated (README.md, CLAUDE.md, or relevant docs)
• No breaking changes (or clearly documented with migration guide if unavoidable)
• GitHub Actions workflows pass (if modified)
• Commit messages are clear and follow conventional commit style