chore: unify code formatting and remove unused code

- Apply cargo fmt to Rust code with multiline error handling
- Apply Prettier formatting to TypeScript code with trailing commas
- Unify #[allow(non_snake_case)] attribute formatting
- Remove unused ProviderNotFound error variant from error.rs
- Add vitest-report.json to .gitignore to exclude test artifacts
- Optimize readability of error handling chains with vertical alignment

All tests passing: 22 Rust tests + 126 frontend tests

src-tauri/src/commands/config.rs

@@ -73,8 +73,7 @@ pub async fn open_config_folder(handle: AppHandle, app: String) -> Result<bool,
 #[tauri::command]
 pub async fn pick_directory(
     app: AppHandle,
-    #[allow(non_snake_case)]
-    defaultPath: Option<String>,
+    #[allow(non_snake_case)] defaultPath: Option<String>,
 ) -> Result<Option<String>, String> {
     let initial = defaultPath
         .map(|p| p.trim().to_string())