feat: Phase 2 — RAG integration in Requirements + DSFA Draft

Add legal context enrichment from Qdrant vector corpus to the two
highest-priority modules (Requirements AI assistant and DSFA drafting
engine).

Go SDK:
- Add SearchCollection() with collection override + whitelist validation
- Refactor Search() to delegate to shared searchInternal()

Python backend:
- New ComplianceRAGClient proxying POST /sdk/v1/rag/search (error-tolerant)
- AI assistant: enrich interpret_requirement() and suggest_controls() with RAG
- Requirements API: add ?include_legal_context=true query parameter

Admin (Next.js):
- Extract shared queryRAG() utility from chat route
- Inject RAG legal context into v1 and v2 draft pipelines

Tests for all three layers (Go, Python, TypeScript shared utility).

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

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

@@ -173,8 +173,22 @@ func (c *LegalRAGClient) generateEmbedding(ctx context.Context, text string) ([]
 	return embResp.Embedding, nil
 }
 
+// SearchCollection queries a specific Qdrant collection for relevant passages.
+// If collection is empty, it falls back to the default collection (bp_compliance_ce).
+func (c *LegalRAGClient) SearchCollection(ctx context.Context, collection string, query string, regulationIDs []string, topK int) ([]LegalSearchResult, error) {
+	if collection == "" {
+		collection = c.collection
+	}
+	return c.searchInternal(ctx, collection, query, regulationIDs, topK)
+}
+
 // Search queries the compliance CE corpus for relevant passages.
 func (c *LegalRAGClient) Search(ctx context.Context, query string, regulationIDs []string, topK int) ([]LegalSearchResult, error) {
+	return c.searchInternal(ctx, c.collection, query, regulationIDs, topK)
+}
+
+// searchInternal performs the actual search against a given collection.
+func (c *LegalRAGClient) searchInternal(ctx context.Context, collection string, query string, regulationIDs []string, topK int) ([]LegalSearchResult, error) {
 	// Generate query embedding via Ollama bge-m3
 	embedding, err := c.generateEmbedding(ctx, query)
 	if err != nil {
@@ -206,7 +220,7 @@ func (c *LegalRAGClient) Search(ctx context.Context, query string, regulationIDs
 	}
 
 	// Call Qdrant
-	url := fmt.Sprintf("http://%s:%s/collections/%s/points/search", c.qdrantHost, c.qdrantPort, c.collection)
+	url := fmt.Sprintf("http://%s:%s/collections/%s/points/search", c.qdrantHost, c.qdrantPort, collection)
 	req, err := http.NewRequestWithContext(ctx, "POST", url, bytes.NewReader(jsonBody))
 	if err != nil {
 		return nil, fmt.Errorf("failed to create search request: %w", err)