Phase 9d: Notification cron + multilingual templates + status badges

Backend (school-service):
  - notification_log table with UNIQUE(event_id, lead_days, audience,
    channel) for idempotent re-runs. Status enum sent/failed/skipped.
  - internal/notifications/templates.go: per-event-type × audience ×
    lead-day-bucket × language templates in 8 languages (de/en/tr/ar/
    uk/ru/pl/fr). Fallback chain (lang→de, eventType→andere) so we
    never miss a render.
  - service.go scans cal_school_event for events whose
    (start_date - runDate) appears in notification_lead_days. For each
    due (audience, channel) tuple it dispatches via POST to the
    Matrix/Email upstreams owned by the colleague's services.
    Empty URL → status='skipped', logged for visibility.
  - dispatcher.go handles the POST, parent-recipient lookup (joins
    parent_account + parent_child + cal_school_event.affected_class_ids),
    and writeLog with the unique constraint dropping duplicate runs.
  - main.go runs a 1-hour ticker; when time.Hour()==6 it invokes the
    scanner for today. Idempotent so transient restarts don't double-
    send.
  - POST /calendar/notifications/run-now for manual trigger + backfill
    (?date=YYYY-MM-DD).
  - GET /calendar/events/:id/notifications returns notification_log
    rows scoped to the owning teacher.
  - MATRIX_SERVICE_URL + EMAIL_SERVICE_URL env vars added (default
    empty = stub mode).

Frontend (studio-v2):
  - NotificationStatus component fetches /events/:id/notifications and
    renders coloured badges per (lead, audience, channel, status).
  - DayDetail mounts NotificationStatus inside each event card when
    notify_parents or notify_students is set.

Tests:
  - 6 new Go unit tests for bucketFor + Render (de/tr/fallback paths)
    + substitute(class_suffix). 89 subtests gesamt.
  - 2 new Playwright tests: badge render with mocked log, hidden when
    notifications are off.

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

school-service/cmd/server/main.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"log"
 	"os"
+	"time"
 
 	"github.com/breakpilot/school-service/internal/config"
 	"github.com/breakpilot/school-service/internal/database"
@@ -37,7 +38,28 @@ func main() {
 	}
 
 	// Create handler
-	handler := handlers.NewHandler(db.Pool, cfg.LLMGatewayURL, cfg.SolverServiceURL)
+	handler := handlers.NewHandler(db.Pool, cfg.LLMGatewayURL, cfg.SolverServiceURL, cfg.MatrixServiceURL, cfg.EmailServiceURL)
+
+	// Phase 9d: daily notification cron. Ticks every hour and runs the
+	// scanner once when the current hour == 6. Idempotent via the
+	// notification_log UNIQUE constraint, so multiple ticks the same day
+	// are safe.
+	go func() {
+		ticker := time.NewTicker(1 * time.Hour)
+		defer ticker.Stop()
+		for {
+			now := time.Now()
+			if now.Hour() == 6 {
+				res, err := handler.NotificationService().RunForDate(context.Background(), now)
+				if err != nil {
+					log.Printf("notification cron error: %v", err)
+				} else {
+					log.Printf("notification cron: %+v", res)
+				}
+			}
+			<-ticker.C
+		}
+	}()
 
 	// Calendar seed — idempotent, runs every boot. Snapshot path is bundled
 	// in the Docker image at /app/internal/seed/calendar_holidays.json. Failures
@@ -263,6 +285,10 @@ func main() {
 		api.GET("/calendar/parents", handler.ListParentInvites)
 		api.POST("/calendar/parents/invite", handler.InviteParent)
 		api.DELETE("/calendar/parents/children/:id", handler.DeleteParentInvite)
+
+		// Phase 9d: notifications.
+		api.POST("/calendar/notifications/run-now", handler.RunNotificationsNow)
+		api.GET("/calendar/events/:id/notifications", handler.ListEventNotifications)
 	}
 
 	// Phase 9c: parent-side endpoints. Auth is the parent session cookie,