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/src/settings_content/workspace.rs

@@ -609,6 +609,10 @@ pub struct ProjectPanelSettingsContent {
     pub drag_and_drop: Option<bool>,
     /// Settings for automatically opening files.
     pub auto_open: Option<ProjectPanelAutoOpenSettings>,
+    /// How to order sibling entries in the project panel.
+    ///
+    /// Default: directories_first
+    pub sort_mode: Option<ProjectPanelSortMode>,
 }
 
 #[derive(
@@ -634,6 +638,31 @@ pub enum ProjectPanelEntrySpacing {
     Standard,
 }
 
+#[derive(
+    Copy,
+    Clone,
+    Debug,
+    Default,
+    Serialize,
+    Deserialize,
+    JsonSchema,
+    MergeFrom,
+    PartialEq,
+    Eq,
+    strum::VariantArray,
+    strum::VariantNames,
+)]
+#[serde(rename_all = "snake_case")]
+pub enum ProjectPanelSortMode {
+    /// Show directories first, then files
+    #[default]
+    DirectoriesFirst,
+    /// Mix directories and files together
+    Mixed,
+    /// Show files first, then directories
+    FilesFirst,
+}
+
 #[skip_serializing_none]
 #[derive(
     Copy, Clone, Debug, Serialize, Deserialize, JsonSchema, MergeFrom, PartialEq, Eq, Default,

crates/settings/src/vscode_import.rs

@@ -668,6 +668,7 @@ impl VsCodeSettings {
             show_diagnostics: self
                 .read_bool("problems.decorations.enabled")
                 .and_then(|b| if b { Some(ShowDiagnostics::Off) } else { None }),
+            sort_mode: None,
             starts_open: None,
             sticky_scroll: None,
             auto_open: None,