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>

README.md

@@ -128,8 +128,8 @@ Know exactly what breaks before you change it. Trace callers, callees, and the f
 <tr>
 <td width="33%" valign="top">
 
-### 🌍 15+ Languages
-TypeScript, JavaScript, Python, Go, Rust, Java, C#, PHP, Ruby, C, C++, Swift, Kotlin—all with the same API.
+### 🌍 17+ Languages
+TypeScript, JavaScript, Python, Go, Rust, Java, C#, PHP, Ruby, C, C++, Swift, Kotlin, Dart, Svelte—all with the same API.
 
 </td>
 <td width="33%" valign="top">
@@ -598,6 +598,8 @@ The `.codegraph/config.json` file controls indexing behavior:
 | C++ | `.cpp`, `.hpp`, `.cc` | Full support |
 | Swift | `.swift` | Basic support |
 | Kotlin | `.kt` | Basic support |
+| Dart | `.dart` | Full support |
+| Svelte | `.svelte` | Full support (script extraction, Svelte 5 runes, SvelteKit routes) |
 
 ## 🔧 Troubleshooting