feat(ai-sdk): classify technical standards (NIST/OWASP/Grundschutz) as technical_standard

The existing NIST corpus (SP 800-82r3 etc., ingested before source_class tagging)
was classified supervisory_guidance because "NIST" sat in guidanceMarkers, so the
control-intent lift (#36) could never surface it. Add a technical_standard class:

- authority.go: new standardMarkers (NIST/OWASP/Grundschutz/ISO 27001/CSA CCM/CIS),
  checked before guidanceMarkers (so "BSI Grundschutz" -> standard, not BSI guidance);
  move NIST out of guidanceMarkers; sourceClassFromWeight maps weight 80 -> standard.
- authority_rerank.go: the intent-lift path (liftAboveBinding + bestBindingSemantic)
  now classifies via classifyAuthority instead of trusting the raw payload source_class,
  so the untagged legacy corpus is recognized — untagged NIST is now lifted on a
  control question ("Welche Controls passen zu Security Updates?").

Tested: classifier cases for NIST/Grundschutz/weight-80, and an untagged-NIST lift case.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

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

@@ -9,8 +9,8 @@ import (
 // authorityInfo is the normative classification of a search result, used internally
 // for re-ranking only (Phase 1 changes ordering, not the response contract).
 type authorityInfo struct {
-	weight       int    // 100 binding_law, 70 guidance, 0 foreign_law, 50 unknown
-	sourceClass  string // binding_law | supervisory_guidance | foreign_law | unknown
+	weight       int    // 100 binding, 80 technical_standard, 70 guidance, 0 foreign, 50 unknown
+	sourceClass  string // binding_law | technical_standard | supervisory_guidance | foreign_law | unknown
 	jurisdiction string // DE | EU | CH
 }
 
@@ -18,7 +18,13 @@ var (
 	guidanceMarkers = []string{
 		"DSK", "EDPB", "BfDI", "BFDI", "BayLfD", "Baylfb", "ENISA", "BSI", "EUCC",
 		"Standards Mapping", "Kpnr", "Orientierungshilfe", "Handreichung", "Beschluss",
-		"Leitlinie", "Guidance", "Empfehlung", "NIST", "OECD", "CISA", "Blue Guide",
+		"Leitlinie", "Guidance", "Empfehlung", "OECD", "CISA", "Blue Guide",
+	}
+	// Technical standards / control frameworks (best-practice controls). Checked BEFORE
+	// guidanceMarkers so a "BSI Grundschutz" chunk classifies as a standard, not BSI guidance.
+	standardMarkers = []string{
+		"NIST", "OWASP", "Grundschutz", "ISO 27001", "ISO/IEC 27001",
+		"CSA CCM", "Cloud Controls Matrix", "CIS Benchmark", "CIS Control",
 	}
 	foreignMarkers = []string{"RevDSG", "fedlex", "(CH)"}
 	deMarkers      = []string{"BDSG", "DSK", "BfDI", "BFDI", "BayLfD", "Baylfb", "BSI"}
@@ -48,6 +54,8 @@ func classifyAuthority(r LegalSearchResult) authorityInfo {
 	switch {
 	case containsAny(hay, foreignMarkers):
 		return authorityInfo{weight: 0, sourceClass: "foreign_law", jurisdiction: "CH"}
+	case r.Category == "standard" || containsAny(hay, standardMarkers):
+		return authorityInfo{weight: 80, sourceClass: "technical_standard", jurisdiction: jur}
 	case r.Category == "guidance" || containsAny(hay, guidanceMarkers):
 		return authorityInfo{weight: 70, sourceClass: "supervisory_guidance", jurisdiction: jur}
 	case r.Category == "regulation" || r.Category == "eu_recht" || normPattern.MatchString(r.ArticleLabel):
@@ -61,6 +69,8 @@ func sourceClassFromWeight(w int) string {
 	switch {
 	case w >= 100:
 		return "binding_law"
+	case w >= 80:
+		return "technical_standard"
 	case w >= 70:
 		return "supervisory_guidance"
 	case w <= 0: