feat: add RAG corpus versioning and source policy backend

Part 1 — RAG Corpus Versioning:
- New DB table compliance_corpus_versions (migration 017)
- Go CorpusVersionStore with CRUD operations
- Assessment struct extended with corpus_version_id
- API endpoints: GET /rag/corpus-status, /rag/corpus-versions/:collection
- RAG routes (search, regulations) now registered in main.go
- Ingestion script registers corpus versions after each run
- Frontend staleness badge in SDK sidebar

Part 3 — Source Policy Backend:
- New FastAPI router with CRUD for allowed sources, PII rules,
  operations matrix, audit trail, stats, and compliance report
- SQLAlchemy models for all source policy tables (migration 001)
- Frontend API base corrected from edu-search:8088/8089 to
  backend-compliance:8002/api

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

ai-compliance-sdk/cmd/server/main.go

@@ -62,6 +62,7 @@ func main() {
 	dsgvoStore := dsgvo.NewStore(pool)
 	uccaStore := ucca.NewStore(pool)
 	escalationStore := ucca.NewEscalationStore(pool)
+	corpusVersionStore := ucca.NewCorpusVersionStore(pool)
 	roadmapStore := roadmap.NewStore(pool)
 	workshopStore := workshop.NewStore(pool)
 	portfolioStore := portfolio.NewStore(pool)
@@ -120,6 +121,7 @@ func main() {
 	vendorHandlers := handlers.NewVendorHandlers(vendorStore)
 	iaceHandler := handlers.NewIACEHandler(iaceStore)
 	trainingHandlers := handlers.NewTrainingHandlers(trainingStore, contentGenerator)
+	ragHandlers := handlers.NewRAGHandlers(corpusVersionStore)
 
 	// Initialize middleware
 	rbacMiddleware := rbac.NewMiddleware(rbacService, policyEngine)
@@ -345,6 +347,15 @@ func main() {
 			uccaRoutes.POST("/dsb-pool", escalationHandlers.AddDSBPoolMember)
 		}
 
+		// RAG routes - Legal Corpus Search & Versioning
+		ragRoutes := v1.Group("/rag")
+		{
+			ragRoutes.POST("/search", ragHandlers.Search)
+			ragRoutes.GET("/regulations", ragHandlers.ListRegulations)
+			ragRoutes.GET("/corpus-status", ragHandlers.CorpusStatus)
+			ragRoutes.GET("/corpus-versions/:collection", ragHandlers.CorpusVersionHistory)
+		}
+
 		// Roadmap routes - Compliance Implementation Roadmaps
 		roadmapRoutes := v1.Group("/roadmaps")
 		{