project_panel: Add Sticky Scroll (#33994)

Closes #7243

- Adds `top_slot_items` to `uniform_list` component to offset list
items.
- Adds `ToPosition` scroll strategy to `uniform_list` to scroll list to
specified index.
- Adds `sticky_items` component which can be used along with
`uniform_list` to add sticky functionality to any view that implements
uniform list.


https://github.com/user-attachments/assets/eb508fa4-167e-4595-911b-52651537284c

Release Notes:

- Added sticky scroll to the project panel, which keeps parent
directories visible while scrolling. This feature is enabled by default.
To disable it, toggle `sticky_scroll` in settings.

crates/project_panel/src/project_panel_settings.rs

@@ -40,6 +40,7 @@ pub struct ProjectPanelSettings {
     pub git_status: bool,
     pub indent_size: f32,
     pub indent_guides: IndentGuidesSettings,
+    pub sticky_scroll: bool,
     pub auto_reveal_entries: bool,
     pub auto_fold_dirs: bool,
     pub scrollbar: ScrollbarSettings,
@@ -150,6 +151,10 @@ pub struct ProjectPanelSettingsContent {
     ///
     /// Default: false
     pub hide_root: Option<bool>,
+    /// Whether to stick parent directories at top of the project panel.
+    ///
+    /// Default: true
+    pub sticky_scroll: Option<bool>,
 }
 
 impl Settings for ProjectPanelSettings {