git_ui: Update commit composer and git status entry UI (#22738)

Blocked on:

- No way to get # of lines changed (added/removed)
- Need methods for:
    - `commit`
    - `stage`
    - `unstage`
- `revert_all` - Similar to Editor::RevertFile, but for all changes in
the project

TODO:

- [ ] Update checkbox visual style to match
[figma](https://www.figma.com/design/sKk3aa7XPwBoE8fdlgp7E8/Git-integration?node-id=804-9255&t=wsHFxPgYHEX78Ky1-11)
- [ ] Update panel button style to filled

- [ ] Panel header
  - [x] Correct 1 change suffix (1 changes -> 1 change)
  - [ ] Add lines changed badge
  - [ ] Add context menu button (`...`)
  - [ ] Add context menu
  - [ ] Wire up Revert All
- [ ] Entry List
  - [x] Revert unwanted ListItem styling
  - [x] Add selected, hover states
  - [ ] Add `scrolled_to_top`, `scrolled_to_bottom`
  - [ ] Show gradient overflow indicator
- [ ] Add `JumpToTop`, `JumpToBottom` actions to the list, bind to shift
+ arrow keys
  - [ ] Remove wrapping from keyboard movement
- [ ] Entry
  - [x] Style deleted entries with a strikethrough
  - [x] `...` on hover or selected
  - [ ] Add context menu
- [ ] Composer
  - Todo...
  
Release Notes:

- N/A

crates/git_ui/src/git_ui.rs

@@ -1,8 +1,8 @@
 use ::settings::Settings;
 use git::repository::GitFileStatus;
-use gpui::{actions, AppContext, Hsla};
+use gpui::{actions, AppContext, Context, Global, Hsla, Model};
 use settings::GitPanelSettings;
-use ui::{Color, Icon, IconName, IntoElement};
+use ui::{Color, Icon, IconName, IntoElement, SharedString};
 
 pub mod git_panel;
 mod settings;
@@ -12,14 +12,45 @@ actions!(
     [
         StageAll,
         UnstageAll,
-        DiscardAll,
+        RevertAll,
         CommitStagedChanges,
-        CommitAllChanges
+        CommitAllChanges,
+        ClearMessage
     ]
 );
 
 pub fn init(cx: &mut AppContext) {
     GitPanelSettings::register(cx);
+    let git_state = cx.new_model(|_cx| GitState::new());
+    cx.set_global(GlobalGitState(git_state));
+}
+
+struct GlobalGitState(Model<GitState>);
+
+impl Global for GlobalGitState {}
+
+pub struct GitState {
+    commit_message: Option<SharedString>,
+}
+
+impl GitState {
+    pub fn new() -> Self {
+        GitState {
+            commit_message: None,
+        }
+    }
+
+    pub fn set_message(&mut self, message: Option<SharedString>) {
+        self.commit_message = message;
+    }
+
+    pub fn clear_message(&mut self) {
+        self.commit_message = None;
+    }
+
+    pub fn get_global(cx: &mut AppContext) -> Model<GitState> {
+        cx.global::<GlobalGitState>().0.clone()
+    }
 }
 
 const ADDED_COLOR: Hsla = Hsla {
@@ -51,6 +82,8 @@ pub fn git_status_icon(status: GitFileStatus) -> impl IntoElement {
             Icon::new(IconName::SquareDot).color(Color::Custom(MODIFIED_COLOR))
         }
         GitFileStatus::Conflict => Icon::new(IconName::Warning).color(Color::Custom(REMOVED_COLOR)),
-        GitFileStatus::Deleted => Icon::new(IconName::Warning).color(Color::Custom(REMOVED_COLOR)),
+        GitFileStatus::Deleted => {
+            Icon::new(IconName::SquareMinus).color(Color::Custom(REMOVED_COLOR))
+        }
     }
 }