feat: make policy length limits configurable per engine (#624)

- Add PolicyLengthConfig struct with max_col, max_file_bytes, and
  max_lines fields, replacing hardcoded constants in the lexer.
- Add Engine::set_policy_length_config and clear_policy_length_config
  to allow callers to override the default limits.
- Add Source::from_contents_with_limits and from_file_with_limits for
  direct Source construction with custom limits; existing from_contents
  and from_file signatures are preserved using defaults.
- Add tests for default rejection, custom limits, and engine plumbing.
- Add bindings for C, C++, Python, WASM/JS, Java, Ruby, C#, Go

bindings/cpp/regorus.hpp

@@ -131,7 +131,15 @@ namespace regorus {
 	Result get_coverage_report_pretty() {
             return Result(regorus_engine_get_coverage_report_pretty(engine));
 	}
-	
+
+	Result set_policy_length_config(RegorusPolicyLengthConfig config) {
+	    return Result(regorus_engine_set_policy_length_config(engine, config));
+	}
+
+	Result clear_policy_length_config() {
+	    return Result(regorus_engine_clear_policy_length_config(engine));
+	}
+
 	~Engine() {
 	    regorus_engine_drop(engine);
 	}