feat(orders): surface order age as colour-coded badge

Replaces the bare formatDate(order.created) string in the order card
metadata slot with an OrderAgeBadge component. The badge shows 'today'
or 'Xd old' with colour coding by bucket (green/amber/orange/red).
The absolute date is preserved in the badge's title= tooltip.

Bucket math lives in src/lib/order-age.ts (covered by 14 unit tests).
This change is rendering-only — no server or schema impact.

Note: dev-server smoke check was blocked by a pre-existing data bug
where the /api/v1/orders/list endpoint returns 0 orders across all tabs
for both admin and david.els users, despite the tab counts showing
22/18/14/17/168/0 — investigated, unrelated to this change. The
OrderAgeBadge will render correctly once that bug is fixed.

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

src/app/(app)/orders/page.tsx

@@ -24,7 +24,8 @@ import {
   Copy,
 } from "lucide-react";
 import getPocketBase from "@/lib/pocketbase";
-import { displayContactName } from "@/lib/utils";
+import { cn, displayContactName } from "@/lib/utils";
+import { getOrderAge, bucketToBadgeClass } from "@/lib/order-age";
 import { isOrderComplete } from "@/lib/server/order-completion";
 import { useAuth } from "@/components/auth-provider";
 import { isRepUser } from "@/lib/rep-visibility";
@@ -96,6 +97,38 @@ function formatDate(dateStr: string): string {
   });
 }
 
+/**
+ * Inline age badge for the order card metadata slot. Kept local to
+ * this file because it's only used here; hoist to
+ * `src/components/order-age-badge.tsx` if a second page needs it.
+ *
+ * The badge text conveys both the relative age ("3d old") and the
+ * bucket colour, and the `title=` preserves the absolute date for
+ * operators who want to know the exact day.
+ */
+function OrderAgeBadge({
+  created,
+  className,
+}: {
+  created: string;
+  className?: string;
+}) {
+  const age = getOrderAge(created);
+  return (
+    <span
+      data-testid={`order-age-badge-${age.bucket}`}
+      className={cn(
+        "rounded-full px-2 py-0.5 text-[10px] font-medium tabular-nums",
+        bucketToBadgeClass(age.bucket),
+        className,
+      )}
+      title={`Created ${formatDate(created)}`}
+    >
+      {age.label}
+    </span>
+  );
+}
+
 async function fetchDashboardJson<T>(url: string): Promise<T> {
   const token = getPocketBase().authStore.token;
   if (!token) throw new Error("Your session has expired. Please sign in again.");
@@ -862,9 +895,10 @@ function OrderCard({
                   </span>
                 </>
               )}
-              <span className="ml-auto text-xs text-muted-foreground hidden sm:inline">
-                {formatDate(order.created)}
-              </span>
+              <OrderAgeBadge
+                  created={order.created}
+                  className="ml-auto hidden sm:inline-flex"
+                />
             </div>
           {/* Per-tab item-count summary — the operator's at-a-glance
               scan line when cards are collapsed. */}