[FEATURE] Option to hide or configure base branch for diff stats in branch status bar

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

When working in repos where PRs target a branch other than master
(e.g., develop), the branch status bar always compares against master,
showing inflated and misleading diff stats (e.g., +24k lines). There is
no way to hide or reconfigure this comparison.

Proposed Solution

Add a setting in settings.json to configure the base branch used for
diff stats in the status bar, or add an option to hide the stats card
entirely. Example:

{
"gitStatusBaseBranch": "develop"
}

This would allow teams with non-master trunk workflows to see accurate
diff stats, or opt out of the display altogether.

Alternative Solutions

_No response_

Priority

Medium - Would be very helpful

Feature Category

Configuration and settings

Use Case Example

_No response_

Additional Context

_No response_