fix(ucca): CM-7 repo_scan is required evidence for attack_surface_minimization

evidence_required lists only required:true rows; repo_scan was required:false so
attack_surface_minimization surfaced config_export alone. An attack-surface scan
IS required to evidence a minimized attack surface. Adds a test pinning the curated
evidence_required set per NIST obligation (the table test only checked control count).

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

ai-compliance-sdk/internal/api/handlers/compliance_graph_handlers_test.go

@@ -95,3 +95,39 @@ func TestObligationStatus_NoFulfillmentClaim(t *testing.T) {
 		}
 	}
 }
+
+// Pin the curated evidence_required set per NIST obligation. A required:false row silently
+// drops from evidence_required, which the table test above (control-count only) would miss.
+func TestObligationStatus_NISTEvidenceTypes(t *testing.T) {
+	r := newComplianceGraphTestRouter(t)
+	want := map[string][]string{
+		"attack_surface_minimization":   {"config_export", "repo_scan"},
+		"software_integrity_protection": {"sbom", "config_export"},
+		"provide_security_updates":      {"config_export", "test_report"},
+	}
+	for ob, exp := range want {
+		_, resp := getObligationStatus(t, r, "?obligation_id="+ob)
+		if len(resp.Controls) != 1 {
+			t.Fatalf("%s: want 1 control, got %d", ob, len(resp.Controls))
+		}
+		if got := resp.Controls[0].EvidenceRequired; !sameStringSet(got, exp) {
+			t.Errorf("%s evidence_required = %v, want %v", ob, got, exp)
+		}
+	}
+}
+
+func sameStringSet(a, b []string) bool {
+	if len(a) != len(b) {
+		return false
+	}
+	m := make(map[string]bool, len(a))
+	for _, x := range a {
+		m[x] = true
+	}
+	for _, x := range b {
+		if !m[x] {
+			return false
+		}
+	}
+	return true
+}