project_panel: Add sort mode (#40160)

Closes #4533 (partly at least)

Release Notes:

- Added `project_panel.sort_mode` option to control explorer file sort
(directories first, mixed, files first)

 ## Summary

Adds three sorting modes for the project panel to give users more
control over how files and directories are displayed:

- **`directories_first`** (default): Current behaviour - directories
grouped before files
- **`mixed`**: Files and directories sorted together alphabetically
- **`files_first`**: filed grouped before directories

 ## Motivation

Users coming from different editors and file managers have different
expectations for file sorting. Some prefer directories grouped at the
top (traditional), while others prefer the macOS Finder-style mixed
sorting where "Apple1/", "apple2.tsx" and "Apple3/" appear
alphabetically mixed together.


 ### Screenshots

New sort options in settings:
<img width="515" height="160" alt="image"
src="https://github.com/user-attachments/assets/8f4e6668-6989-4881-a9bd-ed1f4f0beb40"
/>


Directories first | Mixed | Files first
-------------|-----|-----
<img width="328" height="888" alt="image"
src="https://github.com/user-attachments/assets/308e5c7a-6e6a-46ba-813d-6e268222925c"
/> | <img width="327" height="891" alt="image"
src="https://github.com/user-attachments/assets/8274d8ca-b60f-456e-be36-e35a3259483c"
/> | <img width="328" height="890" alt="image"
src="https://github.com/user-attachments/assets/3c3b1332-cf08-4eaf-9bed-527c00b41529"
/>


### Agent usage

Copilot-cli/claude-code/codex-cli helped out a lot. I'm not from a rust
background, but really wanted this solved, and it gave me a chance to
play with some of the coding agents I'm not permitted to use for work
stuff

---------

Co-authored-by: Smit Barmase <heysmitbarmase@gmail.com>

crates/settings_ui/src/page_data.rs

@@ -3822,6 +3822,24 @@ pub(crate) fn settings_data(cx: &App) -> Vec<SettingsPage> {
                     metadata: None,
                     files: USER,
                 }),
+                SettingsPageItem::SettingItem(SettingItem {
+                    title: "Sort Mode",
+                    description: "Sort order for entries in the project panel.",
+                    field: Box::new(SettingField {
+                        pick: |settings_content| {
+                            settings_content.project_panel.as_ref()?.sort_mode.as_ref()
+                        },
+                        write: |settings_content, value| {
+                            settings_content
+                                .project_panel
+                                .get_or_insert_default()
+                                .sort_mode = value;
+                        },
+                        json_path: Some("project_panel.sort_mode"),
+                    }),
+                    metadata: None,
+                    files: USER,
+                }),
                 SettingsPageItem::SectionHeader("Terminal Panel"),
                 SettingsPageItem::SettingItem(SettingItem {
                     title: "Terminal Dock",

crates/settings_ui/src/settings_ui.rs

@@ -451,6 +451,7 @@ fn init_renderers(cx: &mut App) {
         .add_basic_renderer::<settings::ShowDiagnostics>(render_dropdown)
         .add_basic_renderer::<settings::ShowCloseButton>(render_dropdown)
         .add_basic_renderer::<settings::ProjectPanelEntrySpacing>(render_dropdown)
+        .add_basic_renderer::<settings::ProjectPanelSortMode>(render_dropdown)
         .add_basic_renderer::<settings::RewrapBehavior>(render_dropdown)
         .add_basic_renderer::<settings::FormatOnSave>(render_dropdown)
         .add_basic_renderer::<settings::IndentGuideColoring>(render_dropdown)