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/internal/notifications/templates_test.go

@@ -0,0 +1,75 @@
+package notifications
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestBucketFor(t *testing.T) {
+	cases := []struct {
+		lead int
+		want string
+	}{
+		{-1, "today"}, {0, "today"}, {1, "tomorrow"}, {2, "days"}, {7, "days"},
+	}
+	for _, c := range cases {
+		if got := bucketFor(c.lead); got != c.want {
+			t.Errorf("bucketFor(%d) = %q, want %q", c.lead, got, c.want)
+		}
+	}
+}
+
+func TestRender_GermanParentsToday(t *testing.T) {
+	subject, body := Render("fortbildung", "parents", 0, "de", Vars{
+		Title: "SCHILF", DatePretty: "10.10.2026", ClassName: "5a",
+	})
+	if !strings.Contains(subject, "Heute") || !strings.Contains(subject, "SCHILF") {
+		t.Errorf("expected today + title in subject, got %q", subject)
+	}
+	if !strings.Contains(body, "Liebe Eltern") {
+		t.Errorf("expected greeting in body, got %q", body)
+	}
+	if !strings.Contains(body, "(5a)") {
+		t.Errorf("expected class suffix, got %q", body)
+	}
+}
+
+func TestRender_TurkishStudentTomorrow(t *testing.T) {
+	subject, _ := Render("schulfeier", "students", 1, "tr", Vars{
+		Title: "Yaz şenliği", DatePretty: "12.06.2026",
+	})
+	if !strings.Contains(subject, "Yarın") || !strings.Contains(subject, "Yaz şenliği") {
+		t.Errorf("expected Turkish 'tomorrow' subject, got %q", subject)
+	}
+}
+
+func TestRender_FallbackLanguage(t *testing.T) {
+	// 'xx' isn't supported → falls back to de.
+	subject, _ := Render("klassenfahrt", "parents", 7, "xx", Vars{
+		Title: "Wattenmeer", DatePretty: "15.05.2026", ClassName: "6b",
+	})
+	if !strings.Contains(subject, "In 7 Tagen") {
+		t.Errorf("expected German fallback, got %q", subject)
+	}
+}
+
+func TestRender_FallbackEventType(t *testing.T) {
+	// 'unknown_type' falls back to 'andere'.
+	subject, _ := Render("unknown_type", "parents", 0, "de", Vars{
+		Title: "Sondertermin",
+	})
+	if !strings.Contains(subject, "Heute") || !strings.Contains(subject, "Sondertermin") {
+		t.Errorf("expected today subject after fallback, got %q", subject)
+	}
+}
+
+func TestSubstitute_DropsClassSuffixWhenEmpty(t *testing.T) {
+	out := substitute("X{{class_suffix}}Y", 0, Vars{ClassName: ""})
+	if out != "XY" {
+		t.Errorf("expected XY (no suffix), got %q", out)
+	}
+	out = substitute("X{{class_suffix}}Y", 0, Vars{ClassName: "5a"})
+	if out != "X (5a)Y" {
+		t.Errorf("expected ' (5a)' suffix, got %q", out)
+	}
+}