feat: Add notification services for Email, Telegram, and WhatsApp

- Implement EmailNotifier for sending batch and test notifications via email.
- Implement TelegramNotifier for sending batch and test notifications via Telegram.
- Implement WahaNotifier for sending batch and test notifications via WhatsApp using WAHA API.
- Create migration for client_categories table and update clients table to include category_id.
- Create migration for notification_settings table to manage notification configurations.
- Add ClientCategorySeeder to populate default client categories.
- Create manifest.json for PWA support.
- Implement service worker (sw.js) for caching static assets and offline support.
- Add edit event view for modifying scheduled events.
- Create search results view for displaying search queries.
- Develop notification settings view for configuring notification channels and triggers.

app/Http/Controllers/ClientCategoryController.php

@@ -0,0 +1,71 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Http\Controllers;
+
+use App\Models\ClientCategory;
+use Illuminate\Http\RedirectResponse;
+use Illuminate\Http\Request;
+
+class ClientCategoryController extends Controller
+{
+    public function index()
+    {
+        // Managed inline from the clients page; redirect there
+        return redirect()->route('clients.index');
+    }
+
+    public function store(Request $request): RedirectResponse
+    {
+        $validated = $request->validate([
+            'name'      => 'required|string|max:100',
+            'parent_id' => 'nullable|exists:client_categories,id',
+            'icon'      => 'nullable|string|max:10',
+            'color'     => 'nullable|string|max:20',
+        ]);
+
+        // Auto slug
+        $validated['slug'] = \Illuminate\Support\Str::slug($validated['name']);
+
+        // If slug conflicts, suffix with random
+        if (ClientCategory::where('slug', $validated['slug'])->exists()) {
+            $validated['slug'] .= '-' . substr(uniqid(), -4);
+        }
+
+        ClientCategory::create($validated);
+
+        return back()->with('success', '🏷️ Category added!');
+    }
+
+    public function update(Request $request, ClientCategory $category): RedirectResponse
+    {
+        $validated = $request->validate([
+            'name'      => 'required|string|max:100',
+            'parent_id' => 'nullable|exists:client_categories,id',
+            'icon'      => 'nullable|string|max:10',
+            'color'     => 'nullable|string|max:20',
+        ]);
+
+        // Prevent a category from being its own parent
+        if (isset($validated['parent_id']) && $validated['parent_id'] == $category->id) {
+            $validated['parent_id'] = null;
+        }
+
+        $category->update($validated);
+
+        return back()->with('success', '🏷️ Category updated!');
+    }
+
+    public function destroy(ClientCategory $category): RedirectResponse
+    {
+        // Reassign children to the parent
+        $category->children()->update(['parent_id' => $category->parent_id]);
+        // Detach clients
+        $category->clients()->update(['category_id' => null]);
+
+        $category->delete();
+
+        return back()->with('success', '🏷️ Category removed.');
+    }
+}