Git changes and commit message via UI (unstaged changes, staged chages)

### Feature summary

Add a tab with unstaged changes, staged changes, a commit message box and a commit button

### What problem are you trying to solve?

I tried all the different modes (interactive, plan and autopilot) and worked on three issues. Besides my auto commit issue https://github.com/github/app/issues/419 , I noticed that if I want to a commit myself, I currently don't see any UI to accept changes into a staging area, to discard changes and even to commit.

In another issue, somebody said something about a commit button, but I don't even see a any commit button or a textbox for a commit message. Maybe it's there and I can't find it? I can probably use the terminal and write the Git commands myself but that breaks my workflow.

Would it be possible to a UI for unstaged changes and staged changes, just like in regular Git UIs?

### Proposed solution

_No response_

### Workflow impact

_No response_

### Installation context

_No response_

### Additional context

_No response_