perf(ai-sdk): embed query once across router fan-out + fold umlauts in intent/concept matching

Authority Router re-embedded the query per collection (6x); on dev the embed
endpoint (OVH) is remote so that was 6 round-trips = 7-12s per /retrieve. Embed
once, reuse via ctx across the concurrent per-collection searches.
DetectIntent + ConceptNorms now fold ae/oe/ue/ss so ASCII (Pruefe) and umlaut
(Pruefe) inputs both match.

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

@@ -48,12 +48,12 @@ var legalConceptOntology = []conceptNorm{
 // ConceptNorms returns the load-bearing norm_ids for the concepts named in the
 // query (dedup, order-preserving). Empty if no concept is named.
 func ConceptNorms(query string) []string {
-	q := strings.ToLower(query)
+	q := normalizeGerman(query)
 	seen := map[string]bool{}
 	out := []string{}
 	for _, cn := range legalConceptOntology {
 		for _, kw := range cn.keywords {
-			if strings.Contains(q, kw) {
+			if strings.Contains(q, normalizeGerman(kw)) {
 				for _, nid := range cn.normIDs {
 					if !seen[nid] {
 						seen[nid] = true