Clean up detail-page time formatting

Render ISO timestamps as "23:30 UTC+03:00 17.04.2026" instead of the
raw "2026-04-17T23:30:00+03:00" that the API returns. Applies to the
per-leg station blocks (new LegStation helper) plus the
Registration / Boarding / Deboarding panels.

formatLocalTime now preserves the wall-clock in the source string
(previously `new Date(...)` would shift it to the runtime's locale).
Added formatUtcOffset (UTC±HH:mm) and formatDayMonthYear (DD.MM.YYYY)
helpers next to it.

Also ship the Angular footer notes on the details page (estimated
times / local-time disclaimer) and added BOARD.LOCAL-TIME-NOTE,
BOARD.ESTIMATED-TIME-NOTE keys to all nine locales.

src/shared/utils/datetime/index.ts

@@ -66,6 +66,51 @@ export function formatDate(
   });
 }
 
+const ISO_OFFSET_RE = /^(\d{4})-(\d{2})-(\d{2})T(\d{2}):(\d{2})(?::\d{2})?(Z|[+-]\d{2}:?\d{2})?$/;
+
+const BARE_HH_MM_RE = /^(\d{1,2}):(\d{2})(?::\d{2})?$/;
+
+/**
+ * Return the HH:mm portion of an ISO string without reprojecting it to the
+ * browser's local timezone. The API sends strings like
+ * "2026-04-17T23:30:00+03:00"; `new Date(...)` would shift it to whatever
+ * locale the SSR/client runs in. We want the wall-clock value that was in
+ * the string. Plain "HH:mm" / "HH:mm:ss" inputs pass through unchanged.
+ */
+export function formatLocalTime(iso: string): string {
+  const full = ISO_OFFSET_RE.exec(iso);
+  if (full) return `${full[4]}:${full[5]}`;
+  const bare = BARE_HH_MM_RE.exec(iso);
+  if (bare) return `${bare[1]!.padStart(2, "0")}:${bare[2]}`;
+  return formatTime(iso); // fall back to Date-based formatter
+}
+
+/**
+ * Extract the UTC offset (e.g. "+03:00", "-05:00", "UTC+00:00") from an
+ * ISO string. Returns "UTC±HH:mm" or "" if the string has no offset.
+ */
+export function formatUtcOffset(iso: string): string {
+  const m = ISO_OFFSET_RE.exec(iso);
+  const off = m?.[6];
+  if (!off) return "";
+  if (off === "Z") return "UTC+00:00";
+  const normalized = off.includes(":") ? off : `${off.slice(0, 3)}:${off.slice(3)}`;
+  return `UTC${normalized}`;
+}
+
+/**
+ * "DD.MM.YYYY" — matches the Angular board footer style.
+ */
+export function formatDayMonthYear(iso: string): string {
+  const m = ISO_OFFSET_RE.exec(iso);
+  if (m) return `${m[3]}.${m[2]}.${m[1]}`;
+  const d = new Date(iso);
+  if (Number.isNaN(d.getTime())) return "";
+  const day = String(d.getDate()).padStart(2, "0");
+  const month = String(d.getMonth() + 1).padStart(2, "0");
+  return `${day}.${month}.${d.getFullYear()}`;
+}
+
 /**
  * Calculate the day offset between two dates (ignoring time).
  * Returns 0 if same day, +1 if actual is the next day, etc.