fix(admin): show the cardless trial as a trial in the admin panel

The cardless trial writes trialEndsAt and nothing else, because there is no
Stripe subscription behind it to report trialing. subscriptionStatus stays
FREE, so every admin view reading that column alone showed a live trial as a
free account: On Trial sat at zero, Free Users counted the trials, the user
table badged them Free with an open-ended Active access, the Trialing filter
returned nobody and the growth scoreboard left them out of the paid accounts
table.

Access has always been resolved from the date (hasBillingAccess), so the
display now follows the same date through getEffectiveBillingStatus. Only FREE
is overridden: any other status means Stripe has an opinion worth showing.

lib/billing.ts

@@ -258,6 +258,73 @@ export function getBillingStatusLabel(status: BillingSubscriptionStatus) {
   }
 }
 
+/**
+ * A `where` matching the accounts whose only entitlement is a running cardless
+ * trial: no Stripe subscription behind them, so `subscriptionStatus` is FREE.
+ */
+export function buildCardlessTrialWhereInput(now: Date = new Date()): Prisma.UserWhereInput {
+  return {
+    subscriptionStatus: BillingSubscriptionStatus.FREE,
+    trialEndsAt: { gt: now },
+  };
+}
+
+/**
+ * The status to show for an account, which is not always the one Stripe stored.
+ *
+ * The cardless trial writes `trialEndsAt` and nothing else, because there is no
+ * Stripe subscription behind it to report `trialing`. `subscriptionStatus` stays
+ * FREE, so anything reading that column alone showed a running trial as a free
+ * account: the admin dashboard counted every trial under "Free Users" and left
+ * "On Trial" at zero. Access is already resolved from the date in
+ * `hasBillingAccess`, so what is displayed follows the same date.
+ *
+ * Only FREE is overridden. Every other status means Stripe has an opinion about
+ * this account (an abandoned checkout leaves INCOMPLETE while the trial runs on),
+ * and that opinion is the more useful of the two to show.
+ */
+export function getEffectiveBillingStatus(
+  subject: Pick<BillingAccessSubject, 'subscriptionStatus' | 'trialEndsAt'>,
+  now: Date = new Date()
+): BillingSubscriptionStatus {
+  if (
+    subject.subscriptionStatus === BillingSubscriptionStatus.FREE &&
+    hasActiveTrial(subject.trialEndsAt, now)
+  ) {
+    return BillingSubscriptionStatus.TRIALING;
+  }
+
+  return subject.subscriptionStatus;
+}
+
+/**
+ * A `where` that filters on the displayed status rather than the stored one, so
+ * an admin asking for "Trialing" is handed the cardless trials and one asking
+ * for "Free" is not.
+ */
+export function buildEffectiveBillingStatusWhereInput(
+  status: BillingSubscriptionStatus,
+  now: Date = new Date()
+): Prisma.UserWhereInput {
+  if (status === BillingSubscriptionStatus.TRIALING) {
+    return {
+      OR: [
+        { subscriptionStatus: BillingSubscriptionStatus.TRIALING },
+        buildCardlessTrialWhereInput(now),
+      ],
+    };
+  }
+
+  if (status === BillingSubscriptionStatus.FREE) {
+    return {
+      subscriptionStatus: BillingSubscriptionStatus.FREE,
+      OR: [{ trialEndsAt: null }, { trialEndsAt: { lte: now } }],
+    };
+  }
+
+  return { subscriptionStatus: status };
+}
+
 /**
  * Grants the cardless trial, once per account, and reports whether this call is
  * the one that granted it.