feat(impact): cross-language blast-radius coverage (22 languages + 14 frameworks) (#708)

Completes the cross-file dependency graph behind impact / affected / explore across all 22 supported languages and 14 web frameworks, validated on real-world repos (measured fair-coverage table added to the README). Per-language resolution + framework resolvers/synthesizers (Lua/Luau require, Shopify OS 2.0 Liquid sections, Delphi forms, Rust cross-module + Rocket macros, Swift Fluent, SvelteKit/Nuxt loader/component conventions, RN/Expo bridges). 0 cross-family false edges, full suite green (1187 passed). See #708.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/extraction/tree-sitter-types.ts

@@ -138,6 +138,14 @@ export interface LanguageExtractor {
   isStatic?: (node: SyntaxNode) => boolean;
   /** Check if variable declaration is a constant (const vs let/var) */
   isConst?: (node: SyntaxNode) => boolean;
+  /**
+   * Extract extra symbol-level modifier keywords to persist on the node's
+   * `decorators` list (e.g. Kotlin `expect`/`actual` multiplatform markers).
+   * Called generically for every created node; return undefined/[] when none.
+   * Used by the resolver to link `expect` declarations to their `actual`
+   * implementations across source sets.
+   */
+  extractModifiers?: (node: SyntaxNode) => string[] | undefined;
 
   // --- New config properties ---