Restore all zeroed views + add bulk gift certificate creation

The HTML entity sweep script had a bug where it wrote empty files for any
view that contained no target Unicode characters, zeroing out 215 view files.
All views restored from the pre-sweep commit (cefdf3e).

Bulk gift certificate feature:
- BulkCreateGiftCertificateDto with Quantity (1-500), Amount, Reason, Expiry, Notes
- GenerateBulkGiftCertificatePdfAsync on IPdfService / PdfService: one Letter page
  per cert, reusing the same purple/gold branded ComposeGiftCertificateContent helper
- GiftCertificatesController: BulkCreate GET/POST, BulkResult GET, BulkDownloadPdf POST
- Views: BulkCreate.cshtml (form with live total preview), BulkResult.cshtml (table +
  Download All PDF button that POSTs cert IDs to avoid URL length limits)
- gift-certificate-bulk.js: live preview + spinner/disable on submit
- Index.cshtml: Bulk Create button added alongside New Certificate

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

src/PowderCoating.Web/Views/TaxRates/Index.cshtml

@@ -0,0 +1,108 @@
+@model List<PowderCoating.Core.Entities.TaxRate>
+@{
+    ViewData["Title"] = "Tax Rates";
+}
+
+<div class="d-flex justify-content-between align-items-center mb-4">
+    <div>
+        <h4 class="mb-0">Tax Rates</h4>
+        <p class="text-muted mb-0 small">Named rates used to auto-fill invoice tax percent when a taxable customer is selected.</p>
+    </div>
+    <a asp-action="Create" class="btn btn-primary btn-sm">
+        <i class="bi bi-plus-circle me-1"></i>Add Tax Rate
+    </a>
+</div>
+
+@if (TempData["Success"] != null)
+{
+    <div class="alert alert-success alert-permanent alert-dismissible fade show" role="alert">
+        @TempData["Success"]
+        <button type="button" class="btn-close" data-bs-dismiss="alert"></button>
+    </div>
+}
+@if (TempData["Error"] != null)
+{
+    <div class="alert alert-danger alert-permanent alert-dismissible fade show" role="alert">
+        @TempData["Error"]
+        <button type="button" class="btn-close" data-bs-dismiss="alert"></button>
+    </div>
+}
+
+<div class="card border-0 shadow-sm">
+    <div class="card-body p-0">
+        @if (!Model.Any())
+        {
+            <div class="text-center py-5 text-muted">
+                <i class="bi bi-percent fs-1 d-block mb-3 opacity-25"></i>
+                <p class="mb-1">No tax rates defined yet.</p>
+                <p class="small">Add a rate and mark it as default to auto-populate tax on invoices.</p>
+                <a asp-action="Create" class="btn btn-primary btn-sm mt-2">
+                    <i class="bi bi-plus-circle me-1"></i>Add First Tax Rate
+                </a>
+            </div>
+        }
+        else
+        {
+            <table class="table table-hover mb-0">
+                <thead class="table-light">
+                    <tr>
+                        <th>Name</th>
+                        <th>Rate</th>
+                        <th>State</th>
+                        <th>Description</th>
+                        <th class="text-center">Default</th>
+                        <th class="text-center">Active</th>
+                        <th></th>
+                    </tr>
+                </thead>
+                <tbody>
+                    @foreach (var rate in Model)
+                    {
+                        <tr class="@(!rate.IsActive ? "opacity-50" : "")">
+                            <td>
+                                @rate.Name
+                                @if (rate.IsDefault)
+                                {
+                                    <span class="badge bg-success ms-1">Default</span>
+                                }
+                            </td>
+                            <td>@rate.Rate.ToString("0.##")%</td>
+                            <td>@(rate.State ?? "—")</td>
+                            <td class="text-muted small">@(rate.Description ?? "—")</td>
+                            <td class="text-center">
+                                @if (rate.IsDefault)
+                                {
+                                    <i class="bi bi-check-circle-fill text-success"></i>
+                                }
+                            </td>
+                            <td class="text-center">
+                                <form asp-action="ToggleActive" asp-route-id="@rate.Id" method="post" class="d-inline">
+                                    @Html.AntiForgeryToken()
+                                    <button type="submit" class="btn btn-sm btn-link p-0 border-0"
+                                            title="@(rate.IsActive ? "Deactivate" : "Activate")">
+                                        <i class="bi @(rate.IsActive ? "bi-toggle-on text-success fs-5" : "bi-toggle-off text-muted fs-5")"></i>
+                                    </button>
+                                </form>
+                            </td>
+                            <td class="text-end">
+                                <a asp-action="Edit" asp-route-id="@rate.Id" class="btn btn-sm btn-outline-secondary me-1">
+                                    <i class="bi bi-pencil"></i>
+                                </a>
+                                @if (!rate.IsDefault)
+                                {
+                                    <form asp-action="Delete" asp-route-id="@rate.Id" method="post" class="d-inline"
+                                          onsubmit="return confirm('Delete this tax rate?')">
+                                        @Html.AntiForgeryToken()
+                                        <button type="submit" class="btn btn-sm btn-outline-danger">
+                                            <i class="bi bi-trash"></i>
+                                        </button>
+                                    </form>
+                                }
+                            </td>
+                        </tr>
+                    }
+                </tbody>
+            </table>
+        }
+    </div>
+</div>