Add record to track overridden limits

Before, we were relying on just changing the cards_count in account, but this
could create problems where the system to calculate the next card number fails due
to the unique constraint.

saas/db/migrate/20251215140000_create_account_overridden_limits.rb

@@ -0,0 +1,10 @@
+class CreateAccountOverriddenLimits < ActiveRecord::Migration[8.2]
+  def change
+    create_table :account_overridden_limits, id: :uuid do |t|
+      t.references :account, null: false, type: :uuid, index: { unique: true }
+      t.integer :card_count
+
+      t.timestamps
+    end
+  end
+end

saas/db/saas_schema.rb

@@ -10,7 +10,15 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[8.2].define(version: 2025_12_03_144630) do
+ActiveRecord::Schema[8.2].define(version: 2025_12_15_140000) do
+  create_table "account_overridden_limits", id: :uuid, charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
+    t.uuid "account_id", null: false
+    t.integer "card_count"
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.index ["account_id"], name: "index_account_overridden_limits_on_account_id", unique: true
+  end
+
   create_table "account_subscriptions", id: :uuid, charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
     t.uuid "account_id", null: false
     t.datetime "cancel_at"