Auto-accept plan from plan mode so users can walk away during planning

Problem

When I enter plan mode for a complex task, Claude often takes 10–15 minutes to produce the plan. I then have to sit and wait just to click "Accept" so it can start executing. That's 15 minutes I'll never get back.

The current flow is:

1. Enter plan mode
2. Wait 10–15 min for plan to generate
3. Click "Accept" ← this is the bottleneck
4. Walk away while Claude executes

Proposed Solution

Add an "Auto-accept plan" option that users can click while Claude is still planning. This lets the user say "I trust you, go ahead and execute whatever plan you come up with" and walk away immediately.

The flow becomes:

1. Enter plan mode
2. Click "Auto-accept plan"
3. Walk away — Claude finishes planning, then automatically proceeds to execution

Why this is different from existing requests

• #1754 (auto switch plan → edit): about automatic transition, but doesn't address the user needing to pre-approve
• #21176 (auto-approve write/edit after plan approval): about skipping per-file prompts after you've already approved the plan
• #18523 (configure default dialog option): about which button is highlighted, still requires the user to be present
• #26349 (compact + auto-accept option): about adding a combined option to the dialog, still requires waiting for the plan

All of these assume the user is present when the plan finishes. This request is about letting the user leave before the plan is done.

Use Case

Power users who trust Claude's planning but can't justify sitting idle for 15 minutes waiting for a plan to render just to click one button. This is especially relevant for complex tasks where planning time is longest — exactly the cases where you'd most want to walk away.