Implement database persistence for dashboards, legal, and compliance modules
- Add PostgreSQL persistence for dashboards module (was returning empty vec![])
- Tables: dashboards, dashboard_widgets, dashboard_data_sources, dashboard_filters,
dashboard_widget_data_sources, conversational_queries
- Full CRUD operations with spawn_blocking pattern
- Add PostgreSQL persistence for legal module (was using in-memory HashMap)
- Tables: legal_documents, legal_document_versions, cookie_consents, consent_history,
legal_acceptances, data_deletion_requests, data_export_requests
- GDPR-compliant consent tracking and document management
- Add PostgreSQL persistence for compliance module (was returning empty results)
- Tables: compliance_checks, compliance_issues, compliance_audit_log, compliance_evidence,
compliance_risk_assessments, compliance_risks, compliance_training_records,
compliance_access_reviews
- Support for GDPR, SOC2, ISO27001, HIPAA, PCI-DSS frameworks
- Add migration files for all new tables
- Update schema.rs with new table definitions and joinables
- Register new routes in main.rs
- Add recursion_limit = 512 for macro expansion