fix: catch all exceptions in Telegram email flow + webhook global handler

- processEmail: wrap DB lookup and ChatContact create/update in try-catch
  so any exception sends an error message to the user instead of silently
  failing and leaving state stuck at await_email
- sendOtp: inform user if mail sending fails so they know to wait/retry
- TelegramWebhookController: top-level try-catch returns 200 always so
  Telegram never retries on server errors (retries caused duplicate state resets)
- ChatContact canal_id cast to string to avoid type mismatch on insert

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/Http/Controllers/TelegramWebhookController.php

@@ -4,10 +4,25 @@ namespace App\Http\Controllers;
 
 use App\Services\TelegramBotService;
 use Illuminate\Http\Request;
+use Illuminate\Support\Facades\Log;
 
 class TelegramWebhookController extends Controller
 {
     public function handle(Request $request)
+    {
+        try {
+            return $this->process($request);
+        } catch (\Throwable $e) {
+            Log::error('[TelegramWebhook] Uncaught exception: ' . $e->getMessage(), [
+                'trace' => $e->getTraceAsString(),
+                'body'  => $request->all(),
+            ]);
+            // Always return 200 so Telegram doesn't retry
+            return response()->json(['ok' => true]);
+        }
+    }
+
+    private function process(Request $request)
     {
         $update = $request->all();
         $bot    = new TelegramBotService();
@@ -57,3 +72,4 @@ class TelegramWebhookController extends Controller
         return response()->json(['ok' => true]);
     }
 }
+