feat: encrypt auth config

db/migrate/20260406140414_change_auth_config_to_text_in_captain_custom_tools.rb

@@ -0,0 +1,13 @@
+class ChangeAuthConfigToTextInCaptainCustomTools < ActiveRecord::Migration[7.1]
+  def up
+    change_column :captain_custom_tools, :auth_config, :text, default: nil
+  end
+
+  def down
+    execute <<~SQL.squish
+      ALTER TABLE captain_custom_tools
+      ALTER COLUMN auth_config TYPE jsonb USING auth_config::jsonb,
+      ALTER COLUMN auth_config SET DEFAULT '{}'::jsonb
+    SQL
+  end
+end