Use dedicated sequence record instead of deal with issues with ids and uuids when using the previous approach

db/migrate/20251127000001_create_account_external_id_sequences.rb

@@ -0,0 +1,9 @@
+class CreateAccountExternalIdSequences < ActiveRecord::Migration[8.0]
+  def change
+    create_table :account_external_id_sequences do |t|
+      t.bigint :value, null: false, default: 0
+
+      t.index :value, unique: true
+    end
+  end
+end

db/migrate/20251127000001_create_external_accounts.rb

@@ -1,15 +0,0 @@
-class CreateExternalAccounts < ActiveRecord::Migration[8.0]
-  def up
-    create_table :external_accounts do |t|
-    end
-
-    max_id = Account.maximum(:external_account_id) || 0
-    if max_id > 0
-      execute "INSERT INTO external_accounts (id) VALUES (#{max_id})"
-    end
-  end
-
-  def down
-    drop_table :external_accounts
-  end
-end