Design consistency audit fixes: alerts, cards, dark mode, utilities

Alert sweep (113 alerts, 79 files):
  All persistent static banners now carry alert-permanent so the
  layout's 5-second auto-dismiss cannot swallow guidance, warnings,
  or validation errors. Transient dismissible toasts left untouched.

CSS fixes (site.css):
  .card.shadow-sm      — strips rogue border from ~40 drifted cards
  .card-header.bg-white — rebinds to var(--bs-body-bg) so card
                          headers follow dark/light theme correctly
  Typography utilities  — .text-2xs (.68rem), .text-xs (.73rem)
  Token color classes   — .text-ember, .text-ok, .text-bad,
                          .text-warn, .text-cool, .bg-paper-2
  Layout utilities      — .mw-xs/sm/md/lg replace inline max-width
  Comment              — documents text-ember vs text-primary intent

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

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

@@ -2107,7 +2107,7 @@
                     <input type="number" id="circDiameter" class="form-control" min="0" step="0.01" value="0" oninput="calculateSqFt()">
                 </div>
                 <hr />
-                <div class="alert alert-info mb-0"><strong>Result:</strong> <span id="calcResult">0.00</span> @ViewBag.AreaUnit</div>
+                <div class="alert alert-info alert-permanent mb-0"><strong>Result:</strong> <span id="calcResult">0.00</span> @ViewBag.AreaUnit</div>
             </div>
             <div class="modal-footer">
                 <button type="button" class="btn btn-secondary" data-bs-dismiss="modal">Cancel</button>
@@ -3224,7 +3224,7 @@
                                   placeholder="Brief description of when to use this template"></textarea>
                     </div>
 
-                    <div class="alert alert-light border mb-0">
+                    <div class="alert alert-light alert-permanent border mb-0">
                         <small class="text-muted">
                             <i class="bi bi-info-circle me-1"></i>
                             The customer, special instructions, and all items with their coatings will be copied.