feat: Reinitialize frontend with SvelteKit and TypeScript

- Delete old Vite+Svelte frontend
- Initialize new SvelteKit project with TypeScript
- Configure Tailwind CSS v4 + DaisyUI
- Implement JWT authentication with auto-refresh
- Create login page with form validation (Zod)
- Add protected route guards
- Update Docker configuration for single-stage build
- Add E2E tests with Playwright (6/11 passing)
- Fix Svelte 5 reactivity with $state() runes

Known issues:
- 5 E2E tests failing (timing/async issues)
- Token refresh implementation needs debugging
- Validation error display timing

backend/app/Models/Holiday.php

@@ -0,0 +1,26 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Factories\HasFactory;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Concerns\HasUuids;
+
+class Holiday extends Model
+{
+    use HasFactory, HasUuids;
+
+    protected $primaryKey = 'id';
+    public $incrementing = false;
+    protected $keyType = 'string';
+
+    protected $fillable = [
+        'date',
+        'name',
+        'description',
+    ];
+
+    protected $casts = [
+        'date' => 'date',
+    ];
+}