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/go/pkg/regorus/mod.go

@@ -214,3 +214,32 @@ func (e *Engine) TakePrints() (string, error) {
 
 	return C.GoString(result.output), nil
 }
+
+type PolicyLengthConfig struct {
+	MaxCol       uint32
+	MaxFileBytes uint
+	MaxLines     uint
+}
+
+func (e *Engine) SetPolicyLengthConfig(config PolicyLengthConfig) error {
+	c := C.RegorusPolicyLengthConfig{
+		max_col:       C.uint32_t(config.MaxCol),
+		max_file_bytes: C.size_t(config.MaxFileBytes),
+		max_lines:      C.size_t(config.MaxLines),
+	}
+	result := C.regorus_engine_set_policy_length_config(e.e, c)
+	defer C.regorus_result_drop(result)
+	if result.status != C.Ok {
+		return fmt.Errorf("%s", C.GoString(result.error_message))
+	}
+	return nil
+}
+
+func (e *Engine) ClearPolicyLengthConfig() error {
+	result := C.regorus_engine_clear_policy_length_config(e.e)
+	defer C.regorus_result_drop(result)
+	if result.status != C.Ok {
+		return fmt.Errorf("%s", C.GoString(result.error_message))
+	}
+	return nil
+}