feat: add default Plan mode for Claude Code tasks

[mhenrichsen]

Summary

• When creating a new task with Claude Code, it now defaults to starting in Plan mode (/plan injected via stdin before the prompt)
• Users can override per-task via a checkbox in Advanced Options, or globally via a new toggle in Settings > Tasks
• Only visible when all selected agents support plan mode (currently Claude Code)

Test plan

• Create a new task with Claude Code — verify /plan appears in terminal before the prompt
• Uncheck plan mode in Advanced Options — verify prompt goes directly as CLI arg (no /plan)
• Test with non-Claude agents — verify the plan mode checkbox is hidden
• Test global settings toggle in Settings page
• Test multi-agent task with Claude Code — verify /plan injection works
• Test with no initial prompt + plan mode — verify /plan is sent alone
• Resume existing task — verify /plan is NOT re-sent

🤖 Generated with Claude Code

[vercel]

@mhenrichsen is attempting to deploy a commit to the General Action Team on Vercel.

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[rabanspiegel]

Thank you! I'd like to see this as a setting where you can select whether plan mode should be enabled by default // if supported by provider. Ideally this feature generalizes across providers and is extensible, similar to auto-approve. And then when creating a task it should resolve to present the alternate option. (If you select default === plan mode, then advanced settings should allow to deselect and vice versa)

[nthomsencph]

Great option to have, but I disagree on whether it should be default. It is a divergence from Claude Code standard and, insofar as possible, it should be up to the developer to enable features if needed, not disable them, for a cleaner interface to CC.

[ZacharyHampton]

I would love this as a setting.