feat: Add Discord alert webhook, ContactCategory enum, form request

- Added Discord alert webhook URL to .env.example
- Created ContactCategory enum with humanReadable method
- Implemented ContactSubmissionRequest form request
- Added ContactSubmission model with fillable and casts properties
- Included configurations for Discord alerts and honeypot protection

app/Enums/ContactCategory.php

@@ -0,0 +1,23 @@
+<?php
+
+namespace App\Enums;
+
+enum ContactCategory: string
+{
+    case Question = 'question';
+    case Advertising = 'advertising';
+    case BugReport = 'bug_report';
+    case Feedback = 'feedback';
+    case Other = 'other';
+
+    public function humanReadable(): string
+    {
+        return match ($this) {
+            ContactCategory::Question => 'Question',
+            ContactCategory::Advertising => 'Advertising',
+            ContactCategory::BugReport => 'Bug Report',
+            ContactCategory::Feedback => 'Feedback',
+            ContactCategory::Other => 'Other',
+        };
+    }
+}

app/Http/Requests/ContactSubmissionRequest.php

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+<?php
+
+namespace App\Http\Requests;
+
+use Illuminate\Foundation\Http\FormRequest;
+
+class ContactSubmissionRequest extends FormRequest
+{
+    public function rules(): array
+    {
+        return [
+            'name'     => ['required', 'max:254'],
+            'email'    => ['required', 'email', 'max:254'],
+            'discord'  => ['nullable', 'min:2', 'max:34'],
+            'category' => ['required', 'in:question,advertising,bug_report,feedback,other'],
+            'subject'  => ['required', 'max:254'],
+            'message'  => ['required', 'unique:contact_submissions', 'max:3500'],
+        ];
+    }
+
+    public function authorize(): bool
+    {
+        return true;
+    }
+}

app/Models/ContactSubmission.php

@@ -0,0 +1,23 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Model;
+use App\Enums\ContactCategory;
+
+class ContactSubmission extends Model
+{
+    protected $fillable
+        = [
+            'name',
+            'email',
+            'discord',
+            'category',
+            'subject',
+            'message',
+        ];
+
+    protected $casts = [
+        'category' => ContactCategory::class,
+    ];
+}