Fix the security audit's findings

Fixes the nine findings of security audit run 1 on 2.4.1 (T1-T11).

F1: Uploads that are not complete now count only the bytes the server
received, and a chunk that goes above the storage quota gets 422. An
anonymous uploader can no longer fill the quota with declared sizes.

F2: The share password and the admin login have a second limit without
the address (20 attempts per minute per share and per e-mail), because
a forged X-Forwarded-For changes the address.

F3: The system password gate and the admin check now also run on
Livewire updates, so an old uploader snapshot cannot register files.

F4: The session keeps a fingerprint of the system password's hash.
When the admin changes the system password, earlier verifications end.

F5: The page after the upload opens only in the session that created
the share, and only while recipients can still reach the share.

F6: The share password limit counts an attempt before the password is
checked, so parallel attempts cannot pass it.

F7: The system password has the same two limits (5 per address, 20 in
total per minute).

F8: A password change or reset signs the user's other sessions out.

F9: The only admin cannot delete the account, which would open /setup
to every visitor.

The setup wizard also holds the admin password to the password
defaults, and Livewire applies EnsureAdmin to updates.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

app/Livewire/SetupWizard.php

@@ -5,6 +5,7 @@ namespace App\Livewire;
 use App\Models\User;
 use Illuminate\Support\Facades\Auth;
 use Illuminate\Support\Facades\Hash;
+use Illuminate\Validation\Rules\Password;
 use Livewire\Attributes\Layout;
 use Livewire\Attributes\Validate;
 use Livewire\Component;
@@ -18,11 +19,20 @@ class SetupWizard extends Component
     #[Validate('required|string|email|max:255|unique:users')]
     public string $email = '';
 
-    #[Validate('required|string|min:8|confirmed')]
     public string $password = '';
 
     public string $password_confirmation = '';
 
+    /**
+     * @return array<string, array<int, mixed>>
+     */
+    protected function rules(): array
+    {
+        return [
+            'password' => ['required', 'string', Password::defaults(), 'confirmed'],
+        ];
+    }
+
     public function mount(): void
     {
         if (User::query()->where('is_admin', true)->exists()) {