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  test — superseded by Breeze's Volt-based auth pages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.

tests/Feature/Auth/EmailVerificationTest.php

@@ -0,0 +1,60 @@
+<?php
+
+namespace Tests\Feature\Auth;
+
+use App\Models\User;
+use Illuminate\Auth\Events\Verified;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Illuminate\Support\Facades\Event;
+use Illuminate\Support\Facades\URL;
+use Tests\TestCase;
+
+class EmailVerificationTest extends TestCase
+{
+    use RefreshDatabase;
+
+    public function test_email_verification_screen_can_be_rendered(): void
+    {
+        $user = User::factory()->unverified()->create();
+
+        $response = $this->actingAs($user)->get('/verify-email');
+
+        $response
+            ->assertSeeVolt('pages.auth.verify-email')
+            ->assertStatus(200);
+    }
+
+    public function test_email_can_be_verified(): void
+    {
+        $user = User::factory()->unverified()->create();
+
+        Event::fake();
+
+        $verificationUrl = URL::temporarySignedRoute(
+            'verification.verify',
+            now()->addMinutes(60),
+            ['id' => $user->id, 'hash' => sha1($user->email)]
+        );
+
+        $response = $this->actingAs($user)->get($verificationUrl);
+
+        Event::assertDispatched(Verified::class);
+        $this->assertTrue($user->fresh()->hasVerifiedEmail());
+        $response->assertRedirect(route('sites.index', absolute: false).'?verified=1');
+    }
+
+    public function test_email_is_not_verified_with_invalid_hash(): void
+    {
+        $user = User::factory()->unverified()->create();
+
+        $verificationUrl = URL::temporarySignedRoute(
+            'verification.verify',
+            now()->addMinutes(60),
+            ['id' => $user->id, 'hash' => sha1('wrong-email')]
+        );
+
+        $this->actingAs($user)->get($verificationUrl);
+
+        $this->assertFalse($user->fresh()->hasVerifiedEmail());
+    }
+}