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

db/schema_sqlite.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[8.2].define(version: 2025_11_25_130010) do
+ActiveRecord::Schema[8.2].define(version: 2025_11_27_000001) do
   create_table "accesses", id: :uuid, force: :cascade do |t|
     t.datetime "accessed_at"
     t.uuid "account_id", null: false
@@ -25,6 +25,11 @@ ActiveRecord::Schema[8.2].define(version: 2025_11_25_130010) do
     t.index ["user_id"], name: "index_accesses_on_user_id"
   end
 
+  create_table "account_external_id_sequences", force: :cascade do |t|
+    t.bigint "value", default: 0, null: false
+    t.index ["value"], name: "index_account_external_id_sequences_on_value", unique: true
+  end
+
   create_table "account_join_codes", id: :uuid, force: :cascade do |t|
     t.uuid "account_id", null: false
     t.string "code", limit: 255, null: false