Ruby language plugin for sqry

Implements the LanguagePlugin trait for Ruby, providing:

• AST parsing with tree-sitter
• Scope extraction
• Relation extraction via RubyGraphBuilder (calls, imports, exports, FFI)

Supported Features

• Classes (regular, subclass, singleton class)
• Modules (namespacing and mixins)
• Methods (instance and class methods)
• Singleton methods (class methods via def self.method)
• Visibility modifiers (public, private, protected)
• attr_reader, attr_writer, attr_accessor (property declarations)