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/live/auth/totp_verification.ex

@@ -0,0 +1,90 @@
+defmodule BerrypodWeb.Auth.TotpVerification do
+  use BerrypodWeb, :live_view
+
+  alias Berrypod.Accounts
+
+  @impl true
+  def mount(_params, session, socket) do
+    user_id = session["totp_pending_user_id"]
+    remember_me = session["totp_pending_remember_me"]
+
+    if user_id do
+      {:ok,
+       socket
+       |> assign(:user_id, user_id)
+       |> assign(:remember_me, remember_me)
+       |> assign(:form, to_form(%{"code" => ""}, as: :totp))
+       |> assign(:trigger_submit, false)}
+    else
+      {:ok,
+       socket
+       |> put_flash(:error, "Session expired. Please log in again.")
+       |> redirect(to: ~p"/users/log-in")}
+    end
+  end
+
+  @impl true
+  def render(assigns) do
+    ~H"""
+    <Layouts.app flash={@flash} current_scope={@current_scope}>
+      <div class="setup-page">
+        <div class="setup-header">
+          <.header>
+            Two-factor authentication
+            <:subtitle>
+              Enter the 6-digit code from your authenticator app.
+            </:subtitle>
+          </.header>
+        </div>
+
+        <.form
+          for={@form}
+          id="totp_form"
+          action={~p"/users/verify-totp"}
+          phx-submit="verify"
+          phx-trigger-action={@trigger_submit}
+        >
+          <input type="hidden" name="remember_me" value={to_string(@remember_me)} />
+
+          <.input
+            field={@form[:code]}
+            type="text"
+            label="Verification code"
+            placeholder="000000"
+            inputmode="numeric"
+            pattern="[0-9]*"
+            autocomplete="one-time-code"
+            maxlength="6"
+            autofocus
+            phx-mounted={JS.focus()}
+          />
+
+          <.button variant="primary" class="admin-btn-block">
+            Verify <span aria-hidden="true">&rarr;</span>
+          </.button>
+        </.form>
+
+        <p class="setup-footer admin-text-tertiary">
+          Lost your device? Enter one of your backup codes instead.
+        </p>
+      </div>
+    </Layouts.app>
+    """
+  end
+
+  @impl true
+  def handle_event("verify", %{"totp" => %{"code" => code}}, socket) do
+    user = Accounts.get_user!(socket.assigns.user_id)
+
+    case Accounts.verify_totp(user, code) do
+      :ok ->
+        {:noreply, assign(socket, :trigger_submit, true)}
+
+      :error ->
+        {:noreply,
+         socket
+         |> assign(:form, to_form(%{"code" => ""}, as: :totp))
+         |> put_flash(:error, "Invalid code. Please try again.")}
+    end
+  end
+end