Function is_branch_merged 

pub fn is_branch_merged(branch_name: &str, target_branch: &str) -> Result<bool>

Check if a branch has been merged into a target branch.

Arguments

• branch_name - The branch to check
• target_branch - The target branch to check against (e.g., “main”)

Returns

• Ok(true) if the branch has been merged into the target
• Ok(false) if the branch exists but hasn’t been merged
• Err(_) if git operations fail