Fix invitation email: load relationships and handle mail failures gracefully

The CompanyInvitationMail accesses company, role, and invitedBy
relationships which weren't loaded before sending. Also wrap mail
send in try-catch so the invitation is still created even if the
mailer is misconfigured (logs a warning instead of crashing).

app/Services/InvitationService.php

@@ -52,7 +52,13 @@ class InvitationService
             'expires_at' => Carbon::now()->addDays(7),
         ]);
 
-        Mail::to($email)->send(new CompanyInvitationMail($invitation));
+        $invitation->load(['company', 'role', 'invitedBy']);
+
+        try {
+            Mail::to($email)->send(new CompanyInvitationMail($invitation));
+        } catch (\Exception $e) {
+            \Log::warning('Failed to send invitation email to '.$email.': '.$e->getMessage());
+        }
 
         return $invitation;
     }