separate account settings from shop settings

- Create dedicated /admin/account page for user account management
- Move email, password, and 2FA settings from /admin/settings
- Add Account link to top of admin sidebar navigation
- Add TOTP-based two-factor authentication with NimbleTOTP
- Add TOTP verification LiveView for login flow
- Add AccountController for TOTP session management
- Remove Advanced section from settings (duplicated in dev tools)
- Remove user email from sidebar footer (replaced by Account link)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

lib/berrypod_web/controllers/user_session_controller.ex

@@ -4,7 +4,7 @@ defmodule BerrypodWeb.UserSessionController do
   alias Berrypod.Accounts
   alias BerrypodWeb.UserAuth
 
-  plug BerrypodWeb.Plugs.RateLimit, [type: :login] when action == :create
+  plug BerrypodWeb.Plugs.RateLimit, [type: :login] when action in [:create, :verify_totp]
 
   def create(conn, %{"_action" => "confirmed"} = params) do
     create(conn, params, "User confirmed successfully.")
@@ -15,14 +15,14 @@ defmodule BerrypodWeb.UserSessionController do
   end
 
   # magic link login
-  defp create(conn, %{"user" => %{"token" => token} = user_params}, info) do
+  defp create(conn, %{"user" => %{"token" => token} = user_params} = params, info) do
     case Accounts.login_user_by_magic_link(token) do
       {:ok, {user, tokens_to_disconnect}} ->
         UserAuth.disconnect_sessions(tokens_to_disconnect)
 
         conn
-        |> put_flash(:info, info)
-        |> UserAuth.log_in_user(user, user_params)
+        |> maybe_store_return_to(params)
+        |> maybe_require_totp(user, user_params, info)
 
       _ ->
         conn
@@ -32,13 +32,13 @@ defmodule BerrypodWeb.UserSessionController do
   end
 
   # email + password login
-  defp create(conn, %{"user" => user_params}, info) do
+  defp create(conn, %{"user" => user_params} = params, info) do
     %{"email" => email, "password" => password} = user_params
 
     if user = Accounts.get_user_by_email_and_password(email, password) do
       conn
-      |> put_flash(:info, info)
-      |> UserAuth.log_in_user(user, user_params)
+      |> maybe_store_return_to(params)
+      |> maybe_require_totp(user, user_params, info)
     else
       # In order to prevent user enumeration attacks, don't disclose whether the email is registered.
       conn
@@ -48,6 +48,55 @@ defmodule BerrypodWeb.UserSessionController do
     end
   end
 
+  defp maybe_store_return_to(conn, %{"return_to" => "/" <> _ = return_to}) do
+    put_session(conn, :user_return_to, return_to)
+  end
+
+  defp maybe_store_return_to(conn, _params), do: conn
+
+  defp maybe_require_totp(conn, user, user_params, info) do
+    if Accounts.totp_enabled?(user) do
+      remember_me = user_params["remember_me"] == "true"
+
+      conn
+      |> put_session(:totp_pending_user_id, user.id)
+      |> put_session(:totp_pending_remember_me, remember_me)
+      |> redirect(to: ~p"/users/totp")
+    else
+      conn
+      |> put_flash(:info, info)
+      |> UserAuth.log_in_user(user, user_params)
+    end
+  end
+
+  def verify_totp(conn, %{"totp" => %{"code" => code}, "remember_me" => remember_me}) do
+    user_id = get_session(conn, :totp_pending_user_id)
+
+    if user_id do
+      user = Accounts.get_user!(user_id)
+
+      case Accounts.verify_totp(user, code) do
+        :ok ->
+          user_params = if remember_me == "true", do: %{"remember_me" => "true"}, else: %{}
+
+          conn
+          |> delete_session(:totp_pending_user_id)
+          |> delete_session(:totp_pending_remember_me)
+          |> put_flash(:info, "Welcome back!")
+          |> UserAuth.log_in_user(user, user_params)
+
+        :error ->
+          conn
+          |> put_flash(:error, "Invalid code. Please try again.")
+          |> redirect(to: ~p"/users/totp")
+      end
+    else
+      conn
+      |> put_flash(:error, "Session expired. Please log in again.")
+      |> redirect(to: ~p"/users/log-in")
+    end
+  end
+
   def update_password(conn, %{"user" => user_params} = params) do
     user = conn.assigns.current_scope.user
     true = Accounts.sudo_mode?(user)
@@ -57,7 +106,7 @@ defmodule BerrypodWeb.UserSessionController do
     UserAuth.disconnect_sessions(expired_tokens)
 
     conn
-    |> put_session(:user_return_to, ~p"/admin/settings")
+    |> put_session(:user_return_to, ~p"/admin/account")
     |> create(params, "Password updated successfully!")
   end