Add DB-backed application tokens for the update endpoint

spec/dummy/db/migrate/20260805000002_create_test_owners.rb

@@ -0,0 +1,10 @@
+# Csak a tesztekhez: az ApplicationToken owner-e (a hostban ez pl. AdminUser).
+class CreateTestOwners < ActiveRecord::Migration[8.1]
+  def change
+    create_table :test_owners, id: { type: :bigint, unsigned: true },
+                               charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci" do |t|
+      t.string :name, limit: 128
+      t.timestamps precision: 3, null: true
+    end
+  end
+end