refactor(go/ucca): split policy_engine, legal_rag, ai_act, nis2, financial_policy, dsgvo_module

Split 6 oversized files (719–882 LOC each) into focused files under 500 LOC:
- policy_engine.go → types, loader, eval, gen (4 files)
- legal_rag.go     → types, client, http, context, scroll (5 files)
- ai_act_module.go → module, yaml, obligations (3 files)
- nis2_module.go   → module, yaml, obligations + shared obligation_yaml_types.go (3+1 files)
- financial_policy.go → types, engine (2 files)
- dsgvo_module.go  → module, yaml, obligations (3 files)

All in package ucca, zero exported symbol renames, go test ./internal/ucca/... passes.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

ai-compliance-sdk/internal/ucca/policy_engine_loader.go

@@ -0,0 +1,86 @@
+package ucca
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"gopkg.in/yaml.v3"
+)
+
+// PolicyEngine evaluates intakes against YAML-defined rules
+type PolicyEngine struct {
+	config *PolicyConfig
+}
+
+// NewPolicyEngine creates a new policy engine, loading from the default path.
+// It searches for the policy file in common locations.
+func NewPolicyEngine() (*PolicyEngine, error) {
+	searchPaths := []string{
+		DefaultPolicyPath,
+		filepath.Join(".", "policies", "ucca_policy_v1.yaml"),
+		filepath.Join("..", "policies", "ucca_policy_v1.yaml"),
+		filepath.Join("..", "..", "policies", "ucca_policy_v1.yaml"),
+		"/app/policies/ucca_policy_v1.yaml",
+	}
+
+	var data []byte
+	var err error
+	for _, path := range searchPaths {
+		data, err = os.ReadFile(path)
+		if err == nil {
+			break
+		}
+	}
+
+	if err != nil {
+		return nil, fmt.Errorf("failed to load policy from any known location: %w", err)
+	}
+
+	var config PolicyConfig
+	if err := yaml.Unmarshal(data, &config); err != nil {
+		return nil, fmt.Errorf("failed to parse policy YAML: %w", err)
+	}
+
+	return &PolicyEngine{config: &config}, nil
+}
+
+// NewPolicyEngineFromPath loads policy from a specific file path
+func NewPolicyEngineFromPath(path string) (*PolicyEngine, error) {
+	data, err := os.ReadFile(path)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read policy file: %w", err)
+	}
+
+	var config PolicyConfig
+	if err := yaml.Unmarshal(data, &config); err != nil {
+		return nil, fmt.Errorf("failed to parse policy YAML: %w", err)
+	}
+
+	return &PolicyEngine{config: &config}, nil
+}
+
+// GetPolicyVersion returns the policy version
+func (e *PolicyEngine) GetPolicyVersion() string {
+	return e.config.Policy.Version
+}
+
+// GetAllRules returns all rules in the policy
+func (e *PolicyEngine) GetAllRules() []RuleDef {
+	return e.config.Rules
+}
+
+// GetAllPatterns returns all patterns in the policy
+func (e *PolicyEngine) GetAllPatterns() map[string]PatternDef {
+	return e.config.Patterns
+}
+
+// GetAllControls returns all controls in the policy
+func (e *PolicyEngine) GetAllControls() map[string]ControlDef {
+	return e.config.Controls
+}
+
+// GetProblemSolutions returns problem-solution mappings
+func (e *PolicyEngine) GetProblemSolutions() []ProblemSolutionDef {
+	return e.config.ProblemSolutions
+}