feat: enhance current duty display with remaining time and improved contact links

- Added a new message key for displaying remaining time until the end of the shift in both English and Russian.
- Updated the current duty card to show remaining time with a formatted string.
- Enhanced the contact links to support block layout with icons for phone and Telegram, improving visual presentation.
- Implemented a new utility function to calculate remaining time until the end of the shift.
- Added unit tests for the new functionality, ensuring accurate time calculations and proper rendering of contact links.

webapp/css/states.css

@@ -70,10 +70,23 @@
 .current-duty-card {
   background: var(--surface);
   border-radius: 12px;
+  border-top: 3px solid var(--duty);
   padding: 24px;
   max-width: 360px;
   width: 100%;
   box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
+  animation: card-appear 0.3s ease-out;
+}
+
+@keyframes card-appear {
+  from {
+    opacity: 0;
+    transform: translateY(16px);
+  }
+  to {
+    opacity: 1;
+    transform: translateY(0);
+  }
 }
 
 .current-duty-title {
@@ -83,6 +96,39 @@
   color: var(--text);
 }
 
+.current-duty-live-dot {
+  display: inline-block;
+  width: 10px;
+  height: 10px;
+  border-radius: 50%;
+  background: var(--duty);
+  margin-right: 8px;
+  animation: pulse-dot 1.5s ease-in-out infinite;
+  vertical-align: middle;
+}
+
+@keyframes pulse-dot {
+  0%,
+  100% {
+    opacity: 1;
+    transform: scale(1);
+  }
+  50% {
+    opacity: 0.6;
+    transform: scale(1.15);
+  }
+}
+
+@media (prefers-reduced-motion: reduce) {
+  .current-duty-card {
+    animation: none;
+  }
+  .current-duty-live-dot {
+    animation: none;
+    opacity: 1;
+  }
+}
+
 .current-duty-name {
   margin: 0 0 8px 0;
   font-size: 1.5rem;
@@ -96,10 +142,50 @@
   color: var(--muted);
 }
 
-.current-duty-no-duty,
+.current-duty-remaining {
+  margin: 0 0 12px 0;
+  font-size: 0.95rem;
+  color: var(--muted);
+}
+
+/* No-duty state: icon + prominent text */
+.current-duty-card--no-duty {
+  border-top-color: var(--muted);
+}
+
+.current-duty-no-duty-wrap {
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  text-align: center;
+  margin: 0 0 20px 0;
+  padding: 8px 0;
+}
+
+.current-duty-no-duty-icon {
+  display: block;
+  color: var(--muted);
+  margin-bottom: 16px;
+  line-height: 0;
+}
+
+.current-duty-no-duty-icon svg {
+  display: block;
+  opacity: 0.7;
+}
+
+.current-duty-no-duty {
+  margin: 0;
+  font-size: 1.15rem;
+  font-weight: 500;
+  color: var(--muted);
+  line-height: 1.4;
+  max-width: 20em;
+}
+
 .current-duty-error {
   margin: 0 0 16px 0;
-  color: var(--muted);
+  color: var(--error);
 }
 
 .current-duty-error {
@@ -110,6 +196,43 @@
   margin: 12px 0 20px 0;
 }
 
+.current-duty-contact-row--blocks {
+  display: flex;
+  flex-direction: column;
+  gap: 8px;
+}
+
+.current-duty-contact-block {
+  display: flex;
+  align-items: center;
+  gap: 12px;
+  min-height: 48px;
+  padding: 12px 16px;
+  border-radius: 8px;
+  background: color-mix(in srgb, var(--accent) 12%, transparent);
+  color: var(--accent);
+  text-decoration: none;
+  font-size: 1rem;
+  font-weight: 500;
+  transition: background 0.2s ease;
+}
+
+.current-duty-contact-block:hover,
+.current-duty-contact-block:focus-visible {
+  background: color-mix(in srgb, var(--accent) 20%, transparent);
+  text-decoration: none;
+  color: var(--accent);
+}
+
+.current-duty-contact-block:focus-visible {
+  outline: 2px solid var(--accent);
+  outline-offset: 2px;
+}
+
+.current-duty-contact-block svg {
+  flex-shrink: 0;
+}
+
 .current-duty-contact {
   display: inline-block;
   margin-right: 12px;