Add Svelte language support with SvelteKit framework resolver

- Add 'svelte' to Language type, DEFAULT_CONFIG includes, grammars, and config validation
- Add SvelteExtractor that extracts <script> blocks and delegates to TS/JS TreeSitterExtractor
- Add Svelte framework resolver for runes ($state, $derived, $effect, etc.), store auto-subscriptions, SvelteKit module aliases ($app/*, $env/*, $lib/*), and SvelteKit route detection
- Update README to list Svelte and Dart in supported languages

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/types.ts

@@ -72,6 +72,7 @@ export type Language =
   | 'swift'
   | 'kotlin'
   | 'dart'
+  | 'svelte'
   | 'liquid'
   | 'unknown';
 
@@ -511,6 +512,8 @@ export const DEFAULT_CONFIG: CodeGraphConfig = {
     '**/*.kts',
     // Dart
     '**/*.dart',
+    // Svelte
+    '**/*.svelte',
     // Liquid (Shopify themes)
     '**/*.liquid',
   ],