[BUG] Android: Base branch selection is ignored — working branch always created from main

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Bug Description

When starting a new session on the Android app (</> Code), the user selects a specific base branch (not main) to build the working branch from. However, the system ignores this selection and always creates the working branch (claude/...) from the tip of main.
Steps to Reproduce

Open Claude Code on Android
Start a new task for a repository
Select a specific branch (not main) as the base branch
The system creates a claude/* branch

Expected Behavior

The working branch should be created from the user-selected base branch.
Actual Behavior

The working branch is created from main, regardless of the user's branch selection. git log confirms the working branch points to the same commit as main.
Environment

Platform: Android app
Repository: Private repo with multiple branches (main, dev, feature branches)

Impact

User's intended base branch context is lost — any work may need manual rebase afterward.

What Should Happen?

Expected Behavior

The working branch should be created from the user-selected base branch.
Actual Behavior

The working branch is created from main, regardless of the user's branch selection. git log confirms the working branch points to the same commit as main.
Environment

• Platform: Android app
• Repository: Private repo with multiple branches (main, dev, feature branches)

Error Messages/Logs

Steps to Reproduce

Steps to Reproduce

• Open Claude Code on Android
• Start a new task for a repository
• Select a specific branch (not main) as the base branch
• The system creates a claude/git-branch-setup-* branch

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

1.260202.37

Platform

Other

Operating System

Other

Terminal/Shell

Other

Additional Information

_No response_