feat(boxstore): add configurable expiry for one-time downloads

Introduces a new configuration setting `one_time_download_expiry_seconds` to allow administrators to define a default expiration period for one-time downloads.

The retention logic in `boxstore` has been updated to use this global expiry value when a box is marked as a one-time download and no specific retention period is defined in the manifest.

static/css/app.css

@@ -387,12 +387,51 @@ textarea:disabled {
     :root { --base-font-size: 18px; --ui-scale: 1.88; }
 }
 
-@media (prefers-reduced-motion: reduce) {
-    *,
-    *::before,
-    *::after {
-        animation-duration: 1ms !important;
-        animation-iteration-count: 1 !important;
-        scroll-behavior: auto !important;
-    }
+.start-upload-cta {
+	min-width: 128px;
+	position: relative;
+	overflow: visible;
+	isolation: isolate;
+	font-weight: bold;
+}
+
+.start-upload-cta.is-current-step {
+	animation: start-ready-rainbow-breathe 1150ms ease-in-out infinite;
+	box-shadow: inset -1px -1px 0 #808080, inset 1px 1px 0 #dfdfdf, 0 0 0 1px #000000;
+}
+
+.start-upload-cta.is-current-step::after {
+	content: "";
+	position: absolute;
+	inset: -4px;
+	pointer-events: none;
+	z-index: 1;
+	padding: 4px;
+	background: linear-gradient(90deg, #ff004c, #ffcc00, #00d26a, #00a2ff, #8c48ff, #ff004c, #ffcc00);
+	background-size: 280% 100%;
+	opacity: .9;
+	-webkit-mask: linear-gradient(#000 0 0) content-box, linear-gradient(#000 0 0);
+	-webkit-mask-composite: xor;
+	mask-composite: exclude;
+	animation: start-border-rainbow-slide 1850ms linear infinite;
+}
+
+@keyframes start-ready-rainbow-breathe {
+	0%, 100% { transform: scale(1); }
+	50% { transform: scale(1.02); }
+}
+
+@keyframes start-border-rainbow-slide {
+	from { background-position: 0% 0%; }
+	to { background-position: 200% 0%; }
+}
+
+@media (prefers-reduced-motion: reduce) {
+	*,
+	*::before,
+	*::after {
+		animation-duration: 1ms !important;
+		animation-iteration-count: 1 !important;
+		scroll-behavior: auto !important;
+	}
 }