style: Apply Prettier formatting with 4-space indentation

Applied consistent code formatting across the project using Prettier, now configured to use 4-space indentation instead of tabs.

src/app.d.ts

@@ -2,8 +2,8 @@
 // for information about these interfaces
 // and what to do when importing types
 declare namespace App {
-	// interface Locals {}
-	// interface PageData {}
-	// interface Error {}
-	// interface Platform {}
+    // interface Locals {}
+    // interface PageData {}
+    // interface Error {}
+    // interface Platform {}
 }