[Feature Request] Support worktree isolation for subagents from non-master branches

Bug Description
I want to have the option to start a subagent with "isolation: "worktree"" AND what it will created from my branch (and not from master)

Environment Info

• Platform: darwin
• Terminal: iTerm.app
• Version: 2.1.92
• Feedback ID: 318262f6-9812-4eab-a723-bed221e70719

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My intent is creating a maker-checker-loop, which requires secrecy\isolation from the makers (subagents).
After a discussion with the agent it seems this is not actually possible in Claude.

Me:
Please think again what options does an agent (checker) has to spawn a subagent with a worktree with isolation in mind.
Please specify my options in a concise list

Agent:
Options for a checker agent spawning maker subagents with isolation:

1. isolation: "worktree" — true isolation, but branches off master, not your current branch. Makers won't have temp-commits.

1. isolation: "worktree" + instruct maker to pull/cherry-pick from the feature branch as its first step — true isolation, eventually correct content, but messy and the maker knows about the source branch.

1. No isolation + pre-created worktrees + prompt-based path restriction — correct content (branched off current HEAD), but no hard isolation boundary. Agent could read root.

1. Bash claude CLI spawned from pre-created worktree CWD — true isolation + correct base. But it's outside the Agent tool (no structured result, no SendMessage to continue).

Summary: The Agent tool gives you isolation or the right branch, not both. The CLI approach gives you both but loses the Agent tool's ergonomics.