Add TCPA-compliant SMS consent tracking for prospect quotes

- Quote entity: ProspectSmsConsent (bool) + ProspectSmsConsentedAt (DateTime?) fields
- QuoteDtos: consent fields on Create/Update/Convert DTOs with TCPA guidance text
- Quote Create/Edit views: SMS consent checkbox shown when mobile number is entered
- Quote ConvertToCustomer view: staff must re-confirm consent carries over to customer record
- QuoteApproval: consent state exposed in ViewModel and ApprovalPage for transparency
- Consent timestamp cleared when prospect quote is linked to an existing customer
- Migration: AddProspectSmsConsent

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

src/PowderCoating.Web/Views/Quotes/Create.cshtml

@@ -104,6 +104,19 @@
                             <span asp-validation-for="ProspectPhone" class="text-danger"></span>
                         </div>
                     </div>
+                    <div class="row mt-2" id="prospectSmsConsentRow" style="display:none;">
+                        <div class="col-12">
+                            <div class="form-check">
+                                <input asp-for="ProspectSmsConsent" class="form-check-input" id="ProspectSmsConsent" />
+                                <label class="form-check-label fw-semibold" for="ProspectSmsConsent">
+                                    Customer verbally agreed to receive SMS notifications
+                                </label>
+                            </div>
+                            <small class="text-muted">
+                                <i class="bi bi-shield-check me-1"></i>Only check if the customer explicitly consented to receive text messages (TCPA compliance).
+                            </small>
+                        </div>
+                    </div>
                     <div class="row mt-2 quote-advanced-only">
                         <div class="col-md-6">
                             <label asp-for="ProspectAddress" class="form-label"></label>
@@ -764,8 +777,23 @@
                     if (el) el.removeAttribute('required');
                 });
             }
+            updateProspectSmsConsentVisibility();
         }
 
+        function updateProspectSmsConsentVisibility() {
+            const phoneEl = document.getElementById('prospectPhone');
+            const row = document.getElementById('prospectSmsConsentRow');
+            if (!phoneEl || !row) return;
+            const isProspect = document.getElementById('forProspect')?.checked;
+            row.style.display = (isProspect && phoneEl.value.trim()) ? '' : 'none';
+        }
+
+        document.addEventListener('DOMContentLoaded', function () {
+            const phoneEl = document.getElementById('prospectPhone');
+            if (phoneEl) phoneEl.addEventListener('input', updateProspectSmsConsentVisibility);
+            updateProspectSmsConsentVisibility();
+        });
+
         // Discount type toggle
         function onDiscountTypeChange() {
             const type = document.getElementById('discountTypeSelect').value;