Add "Edit in VS Code" button to the code preview

Code/text files get a VS Code action in the preview header; a backend
open_in_vscode command resolves the depot file to its local working copy
and launches `code <path>` via the shell.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src-tauri/src/lib.rs

@@ -610,6 +610,28 @@ async fn open_in_explorer(state: State<'_, AppState>, target: String) -> Result<
     Ok(())
 }
 
+/// Open a depot file's local working copy in VS Code (`code <path>`).
+/// `code` is a .cmd on Windows, so it must be launched through the shell.
+#[tauri::command]
+async fn open_in_vscode(state: State<'_, AppState>, depot: String) -> Result<(), String> {
+    let conn = current(&state)?;
+    let local = run_json(&conn, &["where", &depot])?
+        .into_iter()
+        .next()
+        .and_then(|v| v.get("path").and_then(|p| p.as_str()).map(String::from))
+        .ok_or_else(|| "Could not resolve the file path".to_string())?;
+    let mut c = Command::new("cmd");
+    #[cfg(windows)]
+    {
+        use std::os::windows::process::CommandExt;
+        c.creation_flags(0x0800_0000);
+    }
+    c.arg("/C").arg(format!("code \"{local}\""));
+    c.spawn()
+        .map_err(|e| format!("VS Code not found (is `code` in PATH?): {e}"))?;
+    Ok(())
+}
+
 /// Open a local file with its associated application (e.g. launch Unreal for a
 /// `.uproject`). Uses the shell `start` so there are no path-scope restrictions.
 #[tauri::command]
@@ -771,6 +793,7 @@ pub fn run() {
             open_in_explorer,
             find_uproject,
             launch_file,
+            open_in_vscode,
             p4_describe,
             read_file,
             read_depot,