[Feature] Configurable Shift+Tab permission-mode cycle (order + subset)

Question

**Feature request**

Two pain points, one fix — an ordered `modeCycle` array in settings.json:

1. **Order (non-monotonic):** cycle is default → acceptEdits → plan → auto. Escalating semi-auto (acceptEdits) → full-auto with one Shift+Tab instead drops into plan — more restrictive — and can halt a task already permitted.
2. **Subset:** users who only use 2 of 3 modes hit a 2-tap guessing game and overshoot.

Proposed:

"permissions": { "modeCycle": ["plan", "default", "acceptEdits", "auto"] }