New commands (parallel to enable-side):
- disable-all [-y|--yes] : disable every active skill, asks confirmation.
- disable-category <prefix> : fzf multi-pick within ACTIVE skills with prefix.
- disable-pick : fzf interactive — choose ACTIVE category → multi-select.
- disable-search [query] : fzf fuzzy search across ACTIVE skills (uses INDEX).
All disable* commands preserve data: they only remove the active copy and
keep (or restore) the parked one. Updated usage text + Notes section.