feat: Add enum member extraction support across all language extractors

Extends AST parsing to identify and extract individual enum members/cases for better code analysis. Adds enumMemberTypes configuration to each language extractor with language-specific node types (e.g., 'enum_variant' for Rust, 'enum_case' for PHP, 'enum_entry' for Swift/Kotlin). Implements flexible member name resolution supporting both field-based and identifier-based extraction patterns.

src/extraction/languages/java.ts

@@ -9,6 +9,7 @@ export const javaExtractor: LanguageExtractor = {
   interfaceTypes: ['interface_declaration'],
   structTypes: [],
   enumTypes: ['enum_declaration'],
+  enumMemberTypes: ['enum_constant'],
   typeAliasTypes: [],
   importTypes: ['import_declaration'],
   callTypes: ['method_invocation'],