Phase 0.5+0.6: consolidate store dirs and save frontend gap analysis

- 0.5: Moved calendarStore.ts from stores/ to store/, removed stores/ dir, updated import
- 0.6: Saved complete frontend gap analysis as frontend-gap-analysis.md (176 lines)
- All stores now in src/store/ (5 stores: authStore, uiStore, commStore, pluginToolbarStore, calendarStore)

frontend/src/store/calendarStore.ts

@@ -0,0 +1,154 @@
+/**
+ * Calendar plugin UI store (zustand).
+ *
+ * Holds view-mode state (day/week/month/range), navigation dates, the list of
+ * calendars the user owns / can write to, the active calendar selection,
+ * which calendars are visible in the grid, and the currently selected entry
+ * for the right-hand detail panel.
+ *
+ * Server state (entries, kanban board) lives in the API hooks layer - this
+ * store only carries view/UI selection state.
+ */
+
+import { create } from 'zustand';
+import type { Calendar, CalendarEntry } from '@/api/calendar';
+
+export type CalendarViewMode = 'day' | 'week' | 'month' | 'range';
+
+export interface CalendarState {
+  /** First day of the visible month (local midnight). */
+  visibleMonth: Date;
+  /** First day (Monday) of the visible week. */
+  visibleWeek: Date;
+  /** The visible day in day-view mode. */
+  visibleDay: Date;
+  /** Start of the date-range view (inclusive). */
+  rangeStart: Date | null;
+  /** End of the date-range view (inclusive). */
+  rangeEnd: Date | null;
+  /** Current view mode. */
+  viewMode: CalendarViewMode;
+  /** Selected calendar id (null = first available). */
+  activeCalendarId: string | null;
+  /** Cached calendar list (filled by fetchCalendars()). */
+  calendars: Calendar[];
+  /** Currently selected entry for the detail panel. */
+  selectedEntry: CalendarEntry | null;
+  /** Set of calendar ids whose entries are shown in the grid (empty = all). */
+  visibleCalendarIds: Set<string>;
+
+  setVisibleMonth: (date: Date) => void;
+  setVisibleWeek: (date: Date) => void;
+  setVisibleDay: (date: Date) => void;
+  setRangeStart: (date: Date | null) => void;
+  setRangeEnd: (date: Date | null) => void;
+  setViewMode: (mode: CalendarViewMode) => void;
+  goToNextMonth: () => void;
+  goToPrevMonth: () => void;
+  goToNextWeek: () => void;
+  goToPrevWeek: () => void;
+  goToNextDay: () => void;
+  goToPrevDay: () => void;
+  goToToday: () => void;
+  setActiveCalendarId: (id: string | null) => void;
+  setCalendars: (calendars: Calendar[]) => void;
+  setSelectedEntry: (entry: CalendarEntry | null) => void;
+  toggleCalendarVisibility: (id: string) => void;
+}
+
+function startOfMonth(d: Date): Date {
+  return new Date(d.getFullYear(), d.getMonth(), 1);
+}
+
+/** Return the Monday of the week containing `d`. */
+function startOfWeek(d: Date): Date {
+  const dayOfWeek = (d.getDay() + 6) % 7; // 0 = Monday
+  const start = new Date(d);
+  start.setDate(d.getDate() - dayOfWeek);
+  start.setHours(0, 0, 0, 0);
+  return start;
+}
+
+function startOfDay(d: Date): Date {
+  return new Date(d.getFullYear(), d.getMonth(), d.getDate());
+}
+
+const today = new Date();
+
+export const useCalendarStore = create<CalendarState>((set) => ({
+  visibleMonth: startOfMonth(today),
+  visibleWeek: startOfWeek(today),
+  visibleDay: startOfDay(today),
+  rangeStart: startOfDay(today),
+  rangeEnd: new Date(today.getFullYear(), today.getMonth(), today.getDate() + 30),
+  viewMode: 'month',
+  activeCalendarId: null,
+  calendars: [],
+  selectedEntry: null,
+  visibleCalendarIds: new Set<string>(),
+
+  setVisibleMonth: (date) => set({ visibleMonth: startOfMonth(date) }),
+  setVisibleWeek: (date) => set({ visibleWeek: startOfWeek(date) }),
+  setVisibleDay: (date) => set({ visibleDay: startOfDay(date) }),
+  setRangeStart: (date) => set({ rangeStart: date ? startOfDay(date) : null }),
+  setRangeEnd: (date) => set({ rangeEnd: date ? startOfDay(date) : null }),
+  setViewMode: (mode) => set({ viewMode: mode }),
+
+  goToNextMonth: () =>
+    set((s) => {
+      const next = new Date(s.visibleMonth);
+      next.setMonth(next.getMonth() + 1);
+      return { visibleMonth: next };
+    }),
+  goToPrevMonth: () =>
+    set((s) => {
+      const next = new Date(s.visibleMonth);
+      next.setMonth(next.getMonth() - 1);
+      return { visibleMonth: next };
+    }),
+  goToNextWeek: () =>
+    set((s) => {
+      const next = new Date(s.visibleWeek);
+      next.setDate(next.getDate() + 7);
+      return { visibleWeek: next };
+    }),
+  goToPrevWeek: () =>
+    set((s) => {
+      const next = new Date(s.visibleWeek);
+      next.setDate(next.getDate() - 7);
+      return { visibleWeek: next };
+    }),
+  goToNextDay: () =>
+    set((s) => {
+      const next = new Date(s.visibleDay);
+      next.setDate(next.getDate() + 1);
+      return { visibleDay: next };
+    }),
+  goToPrevDay: () =>
+    set((s) => {
+      const next = new Date(s.visibleDay);
+      next.setDate(next.getDate() - 1);
+      return { visibleDay: next };
+    }),
+
+  goToToday: () =>
+    set({
+      visibleMonth: startOfMonth(new Date()),
+      visibleWeek: startOfWeek(new Date()),
+      visibleDay: startOfDay(new Date()),
+    }),
+
+  setActiveCalendarId: (id) => set({ activeCalendarId: id }),
+  setCalendars: (calendars) => set({ calendars }),
+  setSelectedEntry: (entry) => set({ selectedEntry: entry }),
+  toggleCalendarVisibility: (id) =>
+    set((s) => {
+      const next = new Set(s.visibleCalendarIds);
+      if (next.has(id)) {
+        next.delete(id);
+      } else {
+        next.add(id);
+      }
+      return { visibleCalendarIds: next };
+    }),
+}));