refactor(go/ucca): split license_policy, models, pdf_export, escalation_store, obligations_registry

Split 5 oversized files (501-583 LOC each) into focused units all under 500 LOC:
- license_policy.go → +_types.go (engine logic / type definitions)
- models.go → +_intake.go, +_assessment.go (enums+domains / intake structs / output+DB types)
- pdf_export.go → +_markdown.go (PDF export / markdown export)
- escalation_store.go → +_dsb.go (main escalation ops / DSB pool ops)
- obligations_registry.go → +_grouping.go (registry core / grouping methods)

All files remain in package ucca. Zero behavior changes.

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

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

@@ -0,0 +1,123 @@
+package ucca
+
+import (
+	"context"
+
+	"github.com/google/uuid"
+)
+
+// ============================================================================
+// DSB Pool Operations
+// ============================================================================
+
+// AddDSBPoolMember adds a member to the DSB review pool.
+func (s *EscalationStore) AddDSBPoolMember(ctx context.Context, m *DSBPoolMember) error {
+	query := `
+		INSERT INTO ucca_dsb_pool (
+			id, tenant_id, user_id, user_name, user_email, role,
+			is_active, max_concurrent_reviews, created_at, updated_at
+		) VALUES (
+			$1, $2, $3, $4, $5, $6, $7, $8, NOW(), NOW()
+		)
+		ON CONFLICT (tenant_id, user_id) DO UPDATE
+		SET user_name = $4, user_email = $5, role = $6,
+			is_active = $7, max_concurrent_reviews = $8, updated_at = NOW()
+	`
+
+	if m.ID == uuid.Nil {
+		m.ID = uuid.New()
+	}
+
+	_, err := s.pool.Exec(ctx, query,
+		m.ID, m.TenantID, m.UserID, m.UserName, m.UserEmail, m.Role,
+		m.IsActive, m.MaxConcurrentReviews,
+	)
+
+	return err
+}
+
+// GetDSBPoolMembers retrieves active DSB pool members for a tenant.
+func (s *EscalationStore) GetDSBPoolMembers(ctx context.Context, tenantID uuid.UUID, role string) ([]DSBPoolMember, error) {
+	query := `
+		SELECT id, tenant_id, user_id, user_name, user_email, role,
+			   is_active, max_concurrent_reviews, current_reviews, created_at, updated_at
+		FROM ucca_dsb_pool
+		WHERE tenant_id = $1 AND is_active = true
+	`
+	args := []interface{}{tenantID}
+
+	if role != "" {
+		query += " AND role = $2"
+		args = append(args, role)
+	}
+
+	query += " ORDER BY current_reviews ASC, user_name ASC"
+
+	rows, err := s.pool.Query(ctx, query, args...)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	var members []DSBPoolMember
+	for rows.Next() {
+		var m DSBPoolMember
+		err := rows.Scan(
+			&m.ID, &m.TenantID, &m.UserID, &m.UserName, &m.UserEmail, &m.Role,
+			&m.IsActive, &m.MaxConcurrentReviews, &m.CurrentReviews, &m.CreatedAt, &m.UpdatedAt,
+		)
+		if err != nil {
+			return nil, err
+		}
+		members = append(members, m)
+	}
+
+	return members, nil
+}
+
+// GetNextAvailableReviewer finds the next available reviewer for a role.
+func (s *EscalationStore) GetNextAvailableReviewer(ctx context.Context, tenantID uuid.UUID, role string) (*DSBPoolMember, error) {
+	query := `
+		SELECT id, tenant_id, user_id, user_name, user_email, role,
+			   is_active, max_concurrent_reviews, current_reviews, created_at, updated_at
+		FROM ucca_dsb_pool
+		WHERE tenant_id = $1 AND is_active = true AND role = $2
+		  AND current_reviews < max_concurrent_reviews
+		ORDER BY current_reviews ASC
+		LIMIT 1
+	`
+
+	var m DSBPoolMember
+	err := s.pool.QueryRow(ctx, query, tenantID, role).Scan(
+		&m.ID, &m.TenantID, &m.UserID, &m.UserName, &m.UserEmail, &m.Role,
+		&m.IsActive, &m.MaxConcurrentReviews, &m.CurrentReviews, &m.CreatedAt, &m.UpdatedAt,
+	)
+
+	if err != nil {
+		return nil, err
+	}
+
+	return &m, nil
+}
+
+// IncrementReviewerCount increments the current review count for a DSB member.
+func (s *EscalationStore) IncrementReviewerCount(ctx context.Context, userID uuid.UUID) error {
+	query := `
+		UPDATE ucca_dsb_pool
+		SET current_reviews = current_reviews + 1, updated_at = NOW()
+		WHERE user_id = $1
+	`
+	_, err := s.pool.Exec(ctx, query, userID)
+	return err
+}
+
+// DecrementReviewerCount decrements the current review count for a DSB member.
+func (s *EscalationStore) DecrementReviewerCount(ctx context.Context, userID uuid.UUID) error {
+	query := `
+		UPDATE ucca_dsb_pool
+		SET current_reviews = GREATEST(0, current_reviews - 1), updated_at = NOW()
+		WHERE user_id = $1
+	`
+	_, err := s.pool.Exec(ctx, query, userID)
+	return err
+}