release/0.20.1

## Changes

- Changes made from outside the app, such as from the `but` CLI, now appear in the desktop app automatically without a manual refresh
- Adds an "Uncommit changes" option to the committed hunk context menu
- Adds Antigravity as a selectable editor for "Open in Editor"
- Redesigned how upstream changes are integrated into a branch: a new update button in the branch list opens a redesigned modal that shows how your branch has diverged from its remote, lets you choose an integration strategy, and previews the result before you apply it

## Fixes

- Fixes a bug where GitHub OAuth failures showed a "missing field" error instead of the actual error response from GitHub
- Fixes an issue where a new branch created on top of pushed commits was incorrectly styled as already pushed; branch styling now follows the branch's own push status
- Fixes the stacked-PR footer "part X of N" count so it matches each PR's position badge
- Fixes an issue where edit-mode refs (`gitbutler/edit`) were left behind after leaving edit mode
- Fixes an issue where "Open in Editor" failed to open the project in Zed

## CLI

- `--json` has been replaced by `--format json`
- Adds `but branch update` to integrate a branch's upstream changes, with selectable strategies (built-in templates or custom steps)
-  Fixes some Codex specific issues causing the tool to underperform compared to Claude Code
- `but` now warns when an agent's skill files are stale and refreshes them automatically
- Fixes a bug where `but apply` reported success and exited 0 even when the branch was left unapplied due to conflicts; it now fails with a clear error
- Fixes a bug where `but rub zz commit` did not amend all changes
- Fixes a bug where `but branch show` could not find branches that were not at the head of a stack
- Fixes a bug where the cache directory was never created, so `but` never stored its update-check result
- Improved the error message when creating a branch whose path prefix collides with an existing branch

## TUI

- You can now mark multiple uncommitted files in the TUI and commit or discard them together
- You can now move multiple uncommitted files at once in the TUI
- Improved the labels shown when moving branches in the TUI

## New Contributors
* @matas-zanevicius made their first contribution in https://github.com/gitbutlerapp/gitbutler/pull/14149
* @AasheeshLikePanner made their first contribution in https://github.com/gitbutlerapp/gitbutler/pull/14114
* @sergeykuzmich made their first contribution in https://github.com/gitbutlerapp/gitbutler/pull/14180
* @allenthich made their first contribution in https://github.com/gitbutlerapp/gitbutler/pull/14231

**Full Changelog**: https://github.com/gitbutlerapp/gitbutler/compare/release/0.20.0...release/0.20.1

## Downloads
Download bins from https://gitbutler.com/