fix: address ESLint warnings and add Vitest configuration

- Add ESLint flat config with Svelte and TypeScript support
- Fix unused variables and component prop naming
- Add Vitest browser testing setup with Playwright
- Configure separate test projects for client and server code

pacman-server/src/auth/mod.rs

@@ -84,4 +84,9 @@ impl AuthRegistry {
     pub fn len(&self) -> usize {
         self.providers.len()
     }
+
+    #[allow(dead_code)]
+    pub fn is_empty(&self) -> bool {
+        self.providers.is_empty()
+    }
 }

pacman-server/src/data/pool.rs

@@ -6,7 +6,7 @@ pub type PgPool = Pool<Postgres>;
 /// Create a PostgreSQL database pool.
 ///
 /// - `immediate`: If true, establishes connection immediately (panics on failure).
-///                If false, uses lazy connection (for tests or when database may not be needed).
+///   If false, uses lazy connection (for tests or when database may not be needed).
 /// - `database_url`: The database connection URL.
 /// - `max_connections`: Maximum number of connections in the pool.
 pub async fn create_pool(immediate: bool, database_url: &str, max_connections: u32) -> PgPool {