fix(tui): gated leading-slash skill breakout on relative match strength

- A skill now surfaces outside the skill: group only when its bare name matches the typed prefix at a strictly stronger tier (exact > prefix > fuzzy) than every non-skill command name and alias; ties keep the popup command-only.
- Skills are scored by bare name as well as full name so a broken-out skill ranks at prefix strength instead of a weak full-name fuzzy hit.