[Feature Request] Reorder permission mode cycling to manual-accept-auto-plan sequence

**Bug Description**
Shift+Tab currently cycles manual → accept-edits → plan → manual, which puts plan mode in the middle of an otherwise monotonic ramp. The three non-plan modes form a natural progression of how much autonomy you're granting — manual approval, then auto-accept edits, then full auto — while plan mode isn't a point on that scale at all; it's a different thing you drop into deliberately.

Ordering the cycle manual → accept → auto → plan keeps the autonomy ramp intact so Shift+Tab reads as "loosen one notch" each press, and parks plan mode at the end of the loop where it's one press back to manual. As it stands you have to pass *through* plan mode to get from accept-edits back to normal, which is both a conceptual detour and an easy way to end up in plan mode by accident. (Opus 5, reviewed)

Related: #72263, #52332. – Rather than have it be configurable, I think a good default would be better.

**Environment Info**
- Platform: darwin
- Terminal: iTerm.app
- Version: 2.1.220
- Feedback ID: db80d2dc-14a7-477b-a0dc-666986bcec0c

Start by locating the Shift+Tab permission-mode cycling entry point and any tests covering mode transitions. Update the sequence to manual → accept-edits → auto → plan → manual, then verify that each press follows this order and that plan mode is only reached at the end of the cycle.

Written by the indexing model from the issue text.