feat: complete commercial control plane, billing, auth, and model catalog

- add PostgreSQL control-plane persistence with Redis-degraded hot reload
- implement prepaid balance, usage ledger, Stripe top-up and reconciliation
- add registration, email verification, password reset, invitations and RBAC
- support TOTP, Passkey MFA, device sessions, quotas and rate limits
- add tenant billing profiles, audit logs and operational readiness checks
- build authenticated admin console, Quickstart, Playground and usage analytics
- add public model catalog with pricing, filtering and cost estimation
- support OpenAI Responses providers and provider health failover
- validate real upstream usage reporting and balance settlement

1 files changed, 31 insertions, 0 deletions

diff --git a/internal/controlplane/preferences_test.go b/internal/controlplane/preferences_test.go
new file mode 100644
index 0000000..88a3d50
--- /dev/null
+++ b/internal/controlplane/preferences_test.go
@@ -0,0 +1,31 @@
+package controlplane
+
+import (
+	"context"
+	"testing"
+)
+
+func TestGetTenantPreferencesWithoutTenantUsesConfiguredDefault(t *testing.T) {
+	result, err := (&Store{}).GetTenantPreferences(context.Background(), "", 12_500_000)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !result.LowBalanceEnabled || result.LowBalanceThresholdMicros != 12_500_000 {
+		t.Fatalf("unexpected defaults: %+v", result)
+	}
+}
+
+func TestPreferenceValidationRejectsUnsafeValuesBeforeDatabaseAccess(t *testing.T) {
+	store := &Store{}
+	if _, err := store.SetDeveloperPreferences(context.Background(), SetDeveloperPreferencesInput{
+		TenantID: "tenant", DefaultModel: "same", FallbackModel: "same",
+	}); err == nil {
+		t.Fatal("expected identical default and fallback models to fail")
+	}
+	threshold := maxLowBalanceThresholdMicros + 1
+	if _, err := store.SetBillingPreferences(context.Background(), SetBillingPreferencesInput{
+		TenantID: "tenant", LowBalanceThresholdMicros: &threshold,
+	}, 5_000_000); err == nil {
+		t.Fatal("expected excessive low balance threshold to fail")
+	}
+}