git: Git Panel UI, continued (#22960)

TODO:

- [ ] Investigate incorrect hit target for `stage all` button
- [ ] Add top level context menu
- [ ] Add entry context menus
- [x] Show paths in list view
- [ ] For now, `enter` can just open the file
- [ ] 🐞: Hover deadzone in list caused by scrollbar
- [x] 🐞: Incorrect status/nothing shown when multiple worktrees are
added

---

This PR continues work on the feature flagged git panel.

Changes:
- Defines and wires up git panel actions & keybindings
- Re-scopes some actions from `git_ui` -> `git`.
- General git actions (StageAll, CommitChanges, ...) are scoped to
`git`.
- Git panel specific actions (Close, FocusCommitEditor, ...) are scoped
to `git_panel.
- Staging actions & UI are now connected to git!
- Unify more reusable git status into the GitState global over being
tied to the panel directly.
- Uses the new git status codepaths instead of filtering all workspace
entries

Release Notes:

- N/A

---------

Co-authored-by: Cole Miller <53574922+cole-miller@users.noreply.github.com>
Co-authored-by: Cole Miller <cole@zed.dev>

Cargo.lock

@@ -5113,6 +5113,7 @@ dependencies = [
  "collections",
  "db",
  "editor",
+ "futures 0.3.31",
  "git",
  "gpui",
  "language",
@@ -5123,6 +5124,7 @@ dependencies = [
  "serde_derive",
  "serde_json",
  "settings",
+ "sum_tree",
  "theme",
  "ui",
  "util",