feat(webui): complete calendar quick access

webui/src/features/calendar/CalendarPage.tsx

@@ -21,6 +21,7 @@ import { ToolbarGroup, ActionToolbar,
   type ApiSettings,
   type AuthInfo
 } from "@govoplan/core-webui";
+import { useLocation, useNavigate } from "react-router";
 import {
   createCalendar,
   createCalendarEvent,
@@ -124,6 +125,8 @@ const modeOptions: {id: CalendarMode;label: string;}[] = [
 
 
 export default function CalendarPage({ settings, auth }: {settings: ApiSettings;auth: AuthInfo;}) {
+  const location = useLocation();
+  const navigate = useNavigate();
   const [calendars, setCalendars] = useState<CalendarCollection[]>([]);
   const [syncSources, setSyncSources] = useState<CalendarSyncSource[]>([]);
   const [visibleCalendarIds, setVisibleCalendarIds] = useState<string[]>([]);
@@ -185,6 +188,38 @@ export default function CalendarPage({ settings, auth }: {settings: ApiSettings;
     void loadCalendars();
   }, [settings.apiBaseUrl, settings.apiKey, settings.accessToken]);
 
+  useEffect(() => {
+    const parameters = new URLSearchParams(location.search);
+    const focusParameter = parameters.get("focusDate");
+    const requestedFocus = validCalendarLaunchDate(focusParameter);
+    if (requestedFocus) setFocusDate(requestedFocus);
+    if (parameters.get("quickAction") !== "create-event" || loading) return;
+
+    const requestedStart = validCalendarLaunchDate(parameters.get("startAt"));
+    if (canWrite && calendars.length > 0 && targetCalendarId) {
+      setFocusDate(requestedStart ?? requestedFocus ?? new Date());
+      setEventDialog({ kind: "create" });
+    }
+
+    parameters.delete("quickAction");
+    parameters.delete("startAt");
+    if (requestedStart) parameters.set("focusDate", requestedStart.toISOString());
+    const search = parameters.toString();
+    navigate(
+      { pathname: location.pathname, search: search ? `?${search}` : "" },
+      { replace: true, state: location.state }
+    );
+  }, [
+    calendars.length,
+    canWrite,
+    loading,
+    location.pathname,
+    location.search,
+    location.state,
+    navigate,
+    targetCalendarId
+  ]);
+
   useEffect(() => {
     saveCalendarMode(mode);
   }, [mode]);
@@ -1083,6 +1118,12 @@ function calendarRemoteMoveBatchId(calendar: CalendarCollection): string {
   return typeof batchId === "string" ? batchId : "";
 }
 
+function validCalendarLaunchDate(value: string | null): Date | null {
+  if (!value) return null;
+  const parsed = new Date(value);
+  return Number.isNaN(parsed.getTime()) ? null : parsed;
+}
+
 function calendarViewPreferences(
   response: CalendarViewPreferencesResponse
 ): CalendarViewPreferences {