feat(dkim): make key size configurable and allow keys to be rotated

db/migrate/20260903100000_add_pending_dkim_fields_to_domains.rb

@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+class AddPendingDKIMFieldsToDomains < ActiveRecord::Migration[7.0]
+
+  def change
+    add_column :domains, :pending_dkim_private_key, :text
+    add_column :domains, :pending_dkim_identifier_string, :string
+  end
+
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[7.0].define(version: 2024_03_11_205229) do
+ActiveRecord::Schema[7.1].define(version: 2026_09_03_100000) do
   create_table "additional_route_endpoints", id: :integer, charset: "utf8mb4", collation: "utf8mb4_general_ci", force: :cascade do |t|
     t.integer "route_id"
     t.string "endpoint_type"
@@ -99,6 +99,8 @@ ActiveRecord::Schema[7.0].define(version: 2024_03_11_205229) do
     t.integer "owner_id"
     t.string "dkim_identifier_string"
     t.boolean "use_for_any"
+    t.text "pending_dkim_private_key"
+    t.string "pending_dkim_identifier_string"
     t.index ["server_id"], name: "index_domains_on_server_id"
     t.index ["uuid"], name: "index_domains_on_uuid", length: 8
   end