feat: add controlled flip functionality to DutyTimelineCard component

- Introduced `isFlipped` and `onFlipChange` props to `DutyTimelineCard` for controlled flipping behavior.
- Updated `DutyList` to manage the flipped state of duty cards, allowing only one card to be flipped at a time.
- Enhanced user interaction by implementing dedicated functions for flipping the card to contacts and back, improving usability.

webapp-next/src/components/duty/DutyList.tsx

@@ -108,6 +108,7 @@ export function DutyList({ scrollMarginTop = 268, className }: DutyListProps) {
 
   const todayKey = localDateString(new Date());
   const [now, setNow] = useState(() => new Date());
+  const [flippedDutyId, setFlippedDutyId] = useState<number | null>(null);
   useEffect(() => {
     const id = setInterval(() => setNow(new Date()), 60_000);
     return () => clearInterval(id);
@@ -209,7 +210,14 @@ export function DutyList({ scrollMarginTop = 268, className }: DutyListProps) {
                         className="min-w-0 overflow-hidden"
                         {...(isCurrent ? { "data-current-duty": true } : {})}
                       >
-                        <DutyTimelineCard duty={duty} isCurrent={isCurrent} />
+                        <DutyTimelineCard
+                          duty={duty}
+                          isCurrent={isCurrent}
+                          isFlipped={flippedDutyId === duty.id}
+                          onFlipChange={(flip) =>
+                            setFlippedDutyId(flip ? duty.id : null)
+                          }
+                        />
                       </div>
                     </div>
                   );

webapp-next/src/components/duty/DutyTimelineCard.tsx

@@ -21,6 +21,10 @@ import { Phone, ArrowLeft } from "lucide-react";
 export interface DutyTimelineCardProps {
   duty: DutyWithUser;
   isCurrent: boolean;
+  /** When provided, card is controlled: only one card can be flipped at a time (managed by parent). */
+  isFlipped?: boolean;
+  /** Called when user flips to contacts (true) or back (false). Used with isFlipped for controlled mode. */
+  onFlipChange?: (flipped: boolean) => void;
 }
 
 function buildTimeStr(duty: DutyWithUser): string {
@@ -48,9 +52,14 @@ const borderByType = {
  * Renders a single duty card. If duty has phone or username, wraps in a flip card
  * (front: type, name, time + "Contacts" button; back: name, ContactLinks, "Back" button).
  */
-export function DutyTimelineCard({ duty, isCurrent }: DutyTimelineCardProps) {
+export function DutyTimelineCard({
+  duty,
+  isCurrent,
+  isFlipped,
+  onFlipChange,
+}: DutyTimelineCardProps) {
   const { t } = useTranslation();
-  const [flipped, setFlipped] = useState(false);
+  const [localFlipped, setLocalFlipped] = useState(false);
   const frontBtnRef = useRef<HTMLButtonElement>(null);
   const backBtnRef = useRef<HTMLButtonElement>(null);
   const hasContacts = Boolean(
@@ -60,13 +69,31 @@ export function DutyTimelineCard({ duty, isCurrent }: DutyTimelineCardProps) {
   const typeLabel = isCurrent
     ? t("duty.now_on_duty")
     : t(`event_type.${duty.event_type || "duty"}`);
-  const timeStr = useMemo(
+  const timeStr = useMemo(() => buildTimeStr(duty), [duty]);
-    () => buildTimeStr(duty),
-    [duty.start_at, duty.end_at]
-  );
   const eventType = (duty.event_type || "duty") as keyof typeof borderByType;
   const borderClass = isCurrent ? "border-l-today" : borderByType[eventType] ?? "border-l-duty";
 
+  const isControlled = onFlipChange != null;
+  const flipped = isControlled ? (isFlipped ?? false) : localFlipped;
+
+  const handleFlipToBack = () => {
+    if (isControlled) {
+      onFlipChange?.(true);
+    } else {
+      setLocalFlipped(true);
+    }
+    setTimeout(() => backBtnRef.current?.focus(), 310);
+  };
+
+  const handleFlipToFront = () => {
+    if (isControlled) {
+      onFlipChange?.(false);
+    } else {
+      setLocalFlipped(false);
+    }
+    setTimeout(() => frontBtnRef.current?.focus(), 310);
+  };
+
   if (!hasContacts) {
     return (
       <div
@@ -121,10 +148,7 @@ export function DutyTimelineCard({ duty, isCurrent }: DutyTimelineCardProps) {
             size="icon"
             className="absolute right-2 top-1/2 -translate-y-1/2 size-9 rounded-full bg-surface text-accent hover:bg-accent/20"
             aria-label={t("contact.show")}
-            onClick={() => {
+            onClick={handleFlipToBack}
-              setFlipped(true);
-              setTimeout(() => backBtnRef.current?.focus(), 310);
-            }}
           >
             <Phone className="size-[18px]" aria-hidden />
           </Button>
@@ -159,10 +183,7 @@ export function DutyTimelineCard({ duty, isCurrent }: DutyTimelineCardProps) {
             size="icon"
             className="absolute right-2 top-1/2 -translate-y-1/2 size-9 rounded-full bg-surface text-accent hover:bg-accent/20"
             aria-label={t("contact.back")}
-            onClick={() => {
+            onClick={handleFlipToFront}
-              setFlipped(false);
-              setTimeout(() => frontBtnRef.current?.focus(), 310);
-            }}
           >
             <ArrowLeft className="size-[18px]" aria-hidden />
           </Button>