Replace hand-rolled auth with Laravel Breeze (Livewire stack)

Adds the auth Breeze scaffolds that were missing before: password
reset and email verification, plus a profile page (update name/email,
change password, delete account). User now implements MustVerifyEmail
so verification is actually enforced, not just scaffolded.

This does mean accepting Tailwind v3 (postcss/tailwind.config.js)
over the v4 CSS-first setup the app started with, and Livewire drops
from ^4.3 to ^3.6.4 — both forced by Breeze/Volt's current
compatibility requirements. Restored the Instrument Sans font Breeze's
installer dropped so styling stays close to what we had.

Reconciliation, since Breeze's installer assumes a blank-slate app:
- Deleted the hand-rolled Login/Register Livewire components/views/
  test — superseded by Breeze's Volt-based auth pages
  (resources/views/livewire/pages/auth/*), which also cover
  forgot-password, reset-password, verify-email, and confirm-password.
- Deleted Breeze's own default welcome/dashboard views and its
  separate app layout + nav component — kept our existing
  components/layouts/app.blade.php as the one real app layout, used
  Breeze's minimal layouts/guest.blade.php only for the auth pages.
- Rewrote routes/web.php merging our routes (home, sites, discover)
  with routes/auth.php; replaced every hardcoded route('dashboard')
  reference (5 Blade files plus, easy to miss, a plain PHP controller
  VerifyEmailController) with sites.index.
- Logout: Breeze's Actions\Logout::__invoke() returns void, so wired
  directly as a route it silently no-ops instead of redirecting;
  fixed with a thin closure that calls it then redirects.
- Fixed Breeze's own generated tests (Auth/AuthenticationTest,
  RegistrationTest, EmailVerificationTest, PasswordConfirmationTest)
  where they assumed the deleted dashboard route/nav component.

Verified: full suite (28 tests, including Breeze's Registration/
Authentication/PasswordReset/PasswordConfirmation/PasswordUpdate/
EmailVerification/Profile tests plus our own GuestPreviewTest) passes
against the huginn_testing MySQL database. Also smoke-tested for real:
all key pages return 200, /profile redirects guests to /login, guest
preview capping still works, and a real password-reset email was
generated and logged with correct branding and a working link.

resources/views/livewire/pages/auth/confirm-password.blade.php

@@ -0,0 +1,62 @@
+<?php
+
+use Illuminate\Support\Facades\Auth;
+use Illuminate\Validation\ValidationException;
+use Livewire\Attributes\Layout;
+use Livewire\Volt\Component;
+
+new #[Layout('layouts.guest')] class extends Component
+{
+    public string $password = '';
+
+    /**
+     * Confirm the current user's password.
+     */
+    public function confirmPassword(): void
+    {
+        $this->validate([
+            'password' => ['required', 'string'],
+        ]);
+
+        if (! Auth::guard('web')->validate([
+            'email' => Auth::user()->email,
+            'password' => $this->password,
+        ])) {
+            throw ValidationException::withMessages([
+                'password' => __('auth.password'),
+            ]);
+        }
+
+        session(['auth.password_confirmed_at' => time()]);
+
+        $this->redirectIntended(default: route('sites.index', absolute: false), navigate: true);
+    }
+}; ?>
+
+<div>
+    <div class="mb-4 text-sm text-gray-600 dark:text-gray-400">
+        {{ __('This is a secure area of the application. Please confirm your password before continuing.') }}
+    </div>
+
+    <form wire:submit="confirmPassword">
+        <!-- Password -->
+        <div>
+            <x-input-label for="password" :value="__('Password')" />
+
+            <x-text-input wire:model="password"
+                          id="password"
+                          class="block mt-1 w-full"
+                          type="password"
+                          name="password"
+                          required autocomplete="current-password" />
+
+            <x-input-error :messages="$errors->get('password')" class="mt-2" />
+        </div>
+
+        <div class="flex justify-end mt-4">
+            <x-primary-button>
+                {{ __('Confirm') }}
+            </x-primary-button>
+        </div>
+    </form>
+</div>