Implement Instance Moderation Notes (#31529)

db/migrate/20250328153843_create_instance_moderation_notes.rb

@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+class CreateInstanceModerationNotes < ActiveRecord::Migration[8.0]
+  def change
+    create_table :instance_moderation_notes do |t|
+      t.string :domain, null: false
+      t.belongs_to :account, foreign_key: { on_delete: :cascade }, index: false, null: false
+      t.text :content
+
+      t.timestamps
+
+      t.index ['domain'], name: 'index_instance_moderation_notes_on_domain'
+    end
+  end
+end