docs(help): list all 6 skills and fix OpenCode command count (#480)

The ponytail-help skills table listed only 4 skills, omitting ponytail-audit
and ponytail-debt (both ship as commands). It also claimed OpenCode ships only
/ponytail and /ponytail-review, when it ships all six. Add the two missing rows
and correct the note. Regenerated the .openclaw copy so it stays in sync.

Closes #437
Closes #438