Feature Request: Native Support for Stacked Pull Requests in VS Code Source Control

I'd really love to see native support for **Stacked Pull Requests** built directly into VS Code and its GitHub integration.

Managing a chain of dependent pull requests can be pretty tedious with the current tooling, and bringing this workflow right into the editor would make a huge difference for developer productivity.

---

### Advantages

* **Better Code Reviews:** Breaking large features into smaller, stacked PRs makes code reviews significantly faster, cleaner, and less prone to bugs for the reviewing team.
* **Streamlined Branch Management:** Instead of manually juggling complex rebases and branch dependencies via the terminal or external tools, developers can handle cascading updates smoothly right inside the editor.
* **Context-Aware AI:** Allowing GitHub Copilot and GitHub Chat to understand the stacked PR structure prevents the AI from getting confused by branch dependencies, helping it give much more accurate suggestions for where to develop next and how to resolve downstream conflicts.

---

### Proposed Features

* **Tree View in Source Control:** * Add a visual tree structure in the Source Control panel to clearly show parent-child branch and PR relationships.
* Display the status of each PR in the stack at a glance (e.g., reviews, checks, outdated status).
* **One-Click Actions:**
* Allow developers to select any branch in the stack and trigger cascading rebases or auto-merges directly from the editor interface.
* **GitHub Chat & Copilot Integration:**
* Give GitHub Chat full awareness of the stacked PR tree so the AI understands dependencies, knows which branch to target for new development, and can assist with cascading rebase conflicts.