feat: Add C# property/field extraction and inheritance support

Addresses C#'s property_declaration nodes (public string Name { get; set; }) by adding propertyTypes support and extractProperty method. Improves field extraction to handle C#'s nested variable_declaration > variable_declarator structure. Adds base_list handling in extractInheritance for C#'s `: Parent, IInterface` syntax where base class and interfaces are combined in a single colon-separated list.

src/extraction/tree-sitter-types.ts

@@ -100,6 +100,8 @@ export interface LanguageExtractor {
   variableTypes: string[];
   /** Node types that represent class fields (extracted as 'field' kind inside class bodies) */
   fieldTypes?: string[];
+  /** Node types that represent class properties (extracted as 'property' kind inside class bodies) */
+  propertyTypes?: string[];
 
   // --- Field name mappings ---