feat: add media supply billing center

server/migrations/20260629110100_add_media_supply_billing_indexes.up.sql

@@ -0,0 +1,12 @@
+CREATE INDEX CONCURRENTLY IF NOT EXISTS idx_media_supply_wallet_ledgers_created_id
+    ON media_supply_wallet_ledgers (created_at DESC, id DESC)
+    INCLUDE (
+        tenant_id,
+        user_id,
+        order_id,
+        reason,
+        delta_cents,
+        sales_cents,
+        cost_cents,
+        gross_profit_cents
+    );