06/16 Phase 6 foundation: admin blueprint, audit log, user management

Adds the admin backend foundation: AuditLog + Setting models/migration,
an admin-only dashboard with KPI cards, and user management (search,
ban/suspend/activate, tier override, trust adjust) with audit logging
on every write action. Smoke suite extended to 64 checks.

app/services/admin_dashboard.py

@@ -0,0 +1,44 @@
+"""Admin dashboard KPI queries. Money returned as integer cents."""
+from datetime import datetime, timedelta
+from app.extensions import db
+from app.models.user import User
+from app.models.listing import Listing
+from app.models.enums import ListingStatus
+from app.models.plan import Plan
+from app.models.payments import Subscription, Transaction
+
+_ACTIVE_SUB_STATUSES = ("active", "trialing")
+
+
+def active_listings_count():
+    return Listing.query.filter(
+        Listing.status == ListingStatus.active,
+        Listing.expires_at > datetime.utcnow(),
+    ).count()
+
+
+def new_users_count(days):
+    since = datetime.utcnow() - timedelta(days=days)
+    return User.query.filter(User.created_at >= since).count()
+
+
+def mrr_cents():
+    """Sum price_monthly_cents for users with an active/trialing subscription."""
+    return (db.session.query(db.func.coalesce(db.func.sum(Plan.price_monthly_cents), 0))
+            .join(Subscription, Subscription.plan_id == Plan.id)
+            .filter(Subscription.status.in_(_ACTIVE_SUB_STATUSES))
+            .scalar())
+
+
+def revenue_30d_cents():
+    """Subscription + boost transactions in the last 30 days."""
+    since = datetime.utcnow() - timedelta(days=30)
+    return (db.session.query(db.func.coalesce(db.func.sum(Transaction.amount_cents), 0))
+            .filter(Transaction.type.in_(("subscription", "boost")),
+                    Transaction.created_at >= since,
+                    Transaction.status == "succeeded")
+            .scalar())
+
+
+def flag_queue_depth():
+    return Listing.query.filter(Listing.flag_count > 0).count()