Fix notification bell, SMS consent kiosk flow, and button alignment

Notification bell:
- Bell now polls /InAppNotifications/Recent every 60s as a SignalR fallback
- Bell dropdown refresh on open so count is always current when staff looks at it

SMS consent → kiosk flow:
- Staff clicks "Get SMS Consent" on Customer Details → AJAX POST to
  /Kiosk/PushSmsConsent stores customer in IMemoryCache (10 min TTL)
- Kiosk PollSession returns smsConsentPending + customerId so tablet navigates
  to /Kiosk/SmsConsent/{customerId} automatically
- Customer reads TCPA consent on tablet, taps I Agree or No Thanks
- On agree: NotifyBySms/SmsConsentedAt/SmsConsentMethod set; in-app notification
  fires; cache cleared; tablet returns to Welcome
- Removed Customers/SmsConsent (staff-browser version); moved view to Kiosk/

Button alignment:
- kiosk.css: added display:flex + align-items:center + justify-content:center to
  all kiosk body buttons so content is centred vertically in tall button outlines

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

src/PowderCoating.Web/Views/Customers/Details.cshtml

@@ -185,11 +185,13 @@
                                         <span class="badge bg-secondary bg-opacity-10 text-secondary border border-secondary border-opacity-25">
                                             <i class="bi bi-chat-slash me-1"></i>SMS off
                                         </span>
-                                        <a href="/Customers/SmsConsent/@Model.Id"
-                                           class="badge bg-primary bg-opacity-10 text-primary border border-primary border-opacity-25 text-decoration-none"
-                                           title="Present SMS consent form to customer">
+                                        <button type="button"
+                                                class="badge bg-primary bg-opacity-10 text-primary border border-primary border-opacity-25 border-0"
+                                                style="cursor:pointer;"
+                                                title="Send SMS consent form to the front-desk kiosk tablet"
+                                                onclick="pushSmsConsent(@Model.Id)">
                                             <i class="bi bi-chat-dots me-1"></i>Get SMS Consent
-                                        </a>
+                                        </button>
                                     }
                                 </div>
                             </div>
@@ -549,3 +551,8 @@
         </div>
     </div>
 }
+
+@section Scripts {
+    <script src="~/js/customer-details.js" asp-append-version="true"></script>
+}
+