Phase 9b: Schul-Events CRUD + Schuljahres-Rollover

Backend (school-service):
  - calendar_events.go — Create/List/Delete on cal_school_event with
    UUID[] handling for affected_class_ids. Default lead-days [7,1]
    if caller omits the array.
  - calendar_rollover.go — single-transaction promotion: graduating
    classes (grade >= 13) get deleted first so the +1 update doesn't
    bump them to invalid grade 14. defaultSchoolYearDates() picks the
    next Aug-Jul pair when the caller doesn't specify.
  - Handlers + routes: GET/POST /calendar/events,
    DELETE /calendar/events/:id, POST /calendar/school-year-rollover.

Frontend (studio-v2):
  - EventModal: form with Title / Typ / Datum/Zeit / unterrichtsfrei /
    Beschreibung / Sichtbarkeit + Notification-Checkboxen. Per-Type
    Farb-Mapping in types.ts.
  - DayDetail: Modal das beim Klick auf einen Kalender-Tag aufgeht und
    Feiertage + Schulferien + Schul-Events fuer diesen Tag listet,
    inkl. Loeschen-Button pro Event.
  - RolloverWizard: zwei-Schritt-Dialog mit Datums-Auswahl + Tipp-
    Bestaetigung ("SCHULJAHR WECHSELN") gegen versehentliche Auslo-
    sung, danach Ergebnis-Card mit promoted/graduated-Counts.
  - MonthView gewinnt onDayClick + onAddEvent + onRollover Props,
    rendert farb-codierte Punkte fuer School-Events am Tagesrand.
  - Page laed Events parallel mit Holidays und reicht alle Handler
    nach unten.

Tests:
  - Go: 3 neue Tests fuer defaultSchoolYearDates + parseClassIDs.
    Validator-Test fuer CreateSchoolEventRequest existiert bereits.
    80 Subtests gesamt, alle gruen.
  - Playwright: mockCalendarApi gewinnt Routes fuer events GET/POST/
    DELETE und school-year-rollover. 6 neue Tests (EventModal open,
    submit, DayDetail open, Rollover-Trigger, Confirm-Schutz,
    Ergebnis-Anzeige).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

studio-v2/app/schulkalender/page.tsx

@@ -6,10 +6,13 @@ import { Sidebar } from '@/components/Sidebar'
 import { ThemeToggle } from '@/components/ThemeToggle'
 import { LanguageDropdown } from '@/components/LanguageDropdown'
 import { calendarApi } from '@/lib/schulkalender/api'
-import type { PublicEvent, SchoolCalendarConfig } from './types'
+import type { PublicEvent, SchoolCalendarConfig, SchoolEvent } from './types'
 import { BUNDESLAENDER } from './types'
 import { MonthView } from './_components/MonthView'
 import { BundeslandWizard } from './_components/BundeslandWizard'
+import { EventModal } from './_components/EventModal'
+import { DayDetail } from './_components/DayDetail'
+import { RolloverWizard } from './_components/RolloverWizard'
 
 function monthRange(year: number, month: number): { from: string; to: string } {
   // Render the visible 6-week grid worth of holidays (covers prev/next month edges).
@@ -27,8 +30,12 @@ export default function SchulkalenderPage() {
   const [month, setMonth] = useState(today.getMonth() + 1)
   const [config, setConfig] = useState<SchoolCalendarConfig | null>(null)
   const [holidays, setHolidays] = useState<PublicEvent[]>([])
+  const [schoolEvents, setSchoolEvents] = useState<SchoolEvent[]>([])
   const [configLoading, setConfigLoading] = useState(true)
   const [error, setError] = useState<string | null>(null)
+  const [openDay, setOpenDay] = useState<string | null>(null)
+  const [showAddModal, setShowAddModal] = useState(false)
+  const [showRollover, setShowRollover] = useState(false)
 
   const loadConfig = useCallback(async () => {
     setConfigLoading(true)
@@ -49,11 +56,15 @@ export default function SchulkalenderPage() {
     if (!config?.bundesland) return
     const { from, to } = monthRange(year, month)
     try {
-      const data = await calendarApi.listHolidays(config.bundesland, from, to)
-      setHolidays(data || [])
+      const [hd, ev] = await Promise.all([
+        calendarApi.listHolidays(config.bundesland, from, to),
+        calendarApi.listEvents(from, to),
+      ])
+      setHolidays(hd || [])
+      setSchoolEvents(ev || [])
       setError(null)
     } catch (e) {
-      setError(e instanceof Error ? e.message : 'Ferien laden fehlgeschlagen')
+      setError(e instanceof Error ? e.message : 'Ferien/Events laden fehlgeschlagen')
     }
   }, [config, year, month])
 
@@ -119,14 +130,45 @@ export default function SchulkalenderPage() {
           ) : !config ? (
             <BundeslandWizard onSave={handleSaveBundesland} />
           ) : (
-            <MonthView
-              year={year}
-              month={month}
-              holidays={holidays}
-              onPrev={goPrev}
-              onNext={goNext}
-              onToday={goToday}
-            />
+            <>
+              <MonthView
+                year={year}
+                month={month}
+                holidays={holidays}
+                schoolEvents={schoolEvents}
+                onPrev={goPrev}
+                onNext={goNext}
+                onToday={goToday}
+                onDayClick={(iso) => setOpenDay(iso)}
+                onAddEvent={() => setShowAddModal(true)}
+                onRollover={() => setShowRollover(true)}
+              />
+
+              {openDay && (
+                <DayDetail
+                  iso={openDay}
+                  holidays={holidays}
+                  events={schoolEvents}
+                  onClose={() => setOpenDay(null)}
+                  onDeleted={() => { loadHolidays(); setOpenDay(null) }}
+                />
+              )}
+
+              {showAddModal && (
+                <EventModal
+                  defaultDate={openDay || new Date().toISOString().slice(0, 10)}
+                  onClose={() => setShowAddModal(false)}
+                  onCreated={() => { setShowAddModal(false); loadHolidays() }}
+                />
+              )}
+
+              {showRollover && (
+                <RolloverWizard
+                  onClose={() => setShowRollover(false)}
+                  onDone={() => { setShowRollover(false); loadHolidays() }}
+                />
+              )}
+            </>
           )}
         </div>
       </main>