Commit All Mode (#24293)

- **Base diffs on uncommitted changes**
- **Show added files in project diff view**
- **Fix git panel optimism**
- **boop**
- **Co-Authored-By: Cole <cole@zed.dev>**
- **Fix commit (all) buttons state**
- **WIP**
- **WIP: commit all mode**

Closes #ISSUE

Release Notes:

- N/A

crates/ui/src/components/icon.rs

@@ -164,6 +164,7 @@ pub enum IconName {
     ChevronRight,
     ChevronUp,
     ChevronUpDown,
+    Circle,
     Close,
     Code,
     Command,

crates/ui/src/components/toggle.rs

@@ -43,6 +43,7 @@ pub struct Checkbox {
     id: ElementId,
     toggle_state: ToggleState,
     disabled: bool,
+    placeholder: bool,
     on_click: Option<Box<dyn Fn(&ToggleState, &mut Window, &mut App) + 'static>>,
     filled: bool,
     style: ToggleStyle,
@@ -62,6 +63,7 @@ impl Checkbox {
             style: ToggleStyle::default(),
             tooltip: None,
             label: None,
+            placeholder: false,
         }
     }
 
@@ -71,6 +73,12 @@ impl Checkbox {
         self
     }
 
+    /// Sets the disabled state of the [`Checkbox`].
+    pub fn placeholder(mut self, placeholder: bool) -> Self {
+        self.placeholder = placeholder;
+        self
+    }
+
     /// Binds a handler to the [`Checkbox`] that will be called when clicked.
     pub fn on_click(
         mut self,
@@ -145,23 +153,26 @@ impl Checkbox {
 impl RenderOnce for Checkbox {
     fn render(self, _: &mut Window, cx: &mut App) -> impl IntoElement {
         let group_id = format!("checkbox_group_{:?}", self.id);
+        let color = if self.disabled {
+            Color::Disabled
+        } else if self.placeholder {
+            Color::Placeholder
+        } else {
+            Color::Selected
+        };
         let icon = match self.toggle_state {
-            ToggleState::Selected => Some(Icon::new(IconName::Check).size(IconSize::Small).color(
-                if self.disabled {
-                    Color::Disabled
-                } else {
-                    Color::Selected
-                },
-            )),
-            ToggleState::Indeterminate => Some(
-                Icon::new(IconName::Dash)
+            ToggleState::Selected => Some(if self.placeholder {
+                Icon::new(IconName::Circle)
+                    .size(IconSize::XSmall)
+                    .color(color)
+            } else {
+                Icon::new(IconName::Check)
                     .size(IconSize::Small)
-                    .color(if self.disabled {
-                        Color::Disabled
-                    } else {
-                        Color::Selected
-                    }),
-            ),
+                    .color(color)
+            }),
+            ToggleState::Indeterminate => {
+                Some(Icon::new(IconName::Dash).size(IconSize::Small).color(color))
+            }
             ToggleState::Unselected => None,
         };