extract setup wizard to dedicated /admin/setup page

Move the setup stepper out of the dashboard into its own LiveView.
Dashboard now redirects to setup when site isn't live, and shows
stats-only view once live. Also cleans up button component variant
handling, fixes alert CSS, and removes stale demo.html.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

lib/berrypod_web/live/auth/confirmation.ex

@@ -26,11 +26,12 @@ defmodule BerrypodWeb.Auth.Confirmation do
             name={@form[:remember_me].name}
             value="true"
             phx-disable-with="Confirming..."
-            class="admin-btn-primary w-full"
+            variant="primary"
+            class="w-full"
           >
             Confirm and stay logged in
           </.button>
-          <.button phx-disable-with="Confirming..." class="admin-btn-soft w-full mt-2">
+          <.button phx-disable-with="Confirming..." class="w-full mt-2">
             Confirm and log in only this time
           </.button>
         </.form>
@@ -46,7 +47,7 @@ defmodule BerrypodWeb.Auth.Confirmation do
         >
           <input type="hidden" name={@form[:token].name} value={@form[:token].value} />
           <%= if @current_scope do %>
-            <.button phx-disable-with="Logging in..." class="admin-btn-primary w-full">
+            <.button phx-disable-with="Logging in..." variant="primary" class="w-full">
               Log in
             </.button>
           <% else %>
@@ -54,11 +55,12 @@ defmodule BerrypodWeb.Auth.Confirmation do
               name={@form[:remember_me].name}
               value="true"
               phx-disable-with="Logging in..."
-              class="admin-btn-primary w-full"
+              variant="primary"
+              class="w-full"
             >
               Keep me logged in on this device
             </.button>
-            <.button phx-disable-with="Logging in..." class="admin-btn-soft w-full mt-2">
+            <.button phx-disable-with="Logging in..." class="w-full mt-2">
               Log me in only this time
             </.button>
           <% end %>

lib/berrypod_web/live/auth/login.ex

@@ -51,7 +51,7 @@ defmodule BerrypodWeb.Auth.Login do
             required
             phx-mounted={JS.focus()}
           />
-          <.button class="admin-btn-primary w-full">
+          <.button variant="primary" class="w-full">
             Log in with email <span aria-hidden="true">→</span>
           </.button>
         </.form>
@@ -80,10 +80,10 @@ defmodule BerrypodWeb.Auth.Login do
             label="Password"
             autocomplete="current-password"
           />
-          <.button class="admin-btn-primary w-full" name={@form[:remember_me].name} value="true">
+          <.button variant="primary" class="w-full" name={@form[:remember_me].name} value="true">
             Log in and stay logged in <span aria-hidden="true">→</span>
           </.button>
-          <.button class="admin-btn-soft w-full mt-2">
+          <.button class="w-full mt-2">
             Log in only this time
           </.button>
         </.form>

lib/berrypod_web/live/auth/registration.ex

@@ -32,7 +32,7 @@ defmodule BerrypodWeb.Auth.Registration do
             phx-mounted={JS.focus()}
           />
 
-          <.button phx-disable-with="Creating account..." class="admin-btn-primary w-full">
+          <.button phx-disable-with="Creating account..." variant="primary" class="w-full">
             Create an account
           </.button>
         </.form>