Auto mode selected at plan approval persists after execution completes

Preflight Checklist

• [x] I have searched existing requests and this hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Current Behavior

When approving a plan with "Yes, and use auto mode," Claude Code switches to auto mode for execution. After execution completes, the session remains in auto mode indefinitely.

Expected Behavior

Auto mode activated via plan approval should be scoped to that execution. Once Claude stops, the session should return to the mode it was in before the plan was approved — or, if the session started in plan mode via defaultMode, to that configured default.

Why This Is Surprising

"Yes, and use auto mode" expresses intent to execute this plan autonomously — not to permanently change the session's mode. Persisting auto mode after the plan finishes means the user is back in a planning or review context but Claude is still operating without permission prompts.