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.go

@@ -0,0 +1,254 @@
+package notifications
+
+import (
+	"fmt"
+	"strings"
+)
+
+// Vars are the placeholder values rendered into a template string.
+// The fields here must match the {{…}} markers in templates below.
+type Vars struct {
+	Title       string
+	Date        string // YYYY-MM-DD
+	DatePretty  string // e.g. "Donnerstag, 15. Oktober"
+	ClassName   string // empty = whole school
+	TeacherName string
+}
+
+// Render picks the right template based on event type, audience, lead-day
+// bucket and language, then substitutes the {{var}} placeholders.
+//
+// lead is grouped into three buckets:
+//   0    → "today"
+//   1    → "tomorrow"
+//   >=2  → "in X days" with X = lead value
+//
+// Falls back through (lang → de) and (event_type → "andere") so we never
+// fail to render even with custom rule combos.
+func Render(eventType, audience string, lead int, lang string, v Vars) (subject, body string) {
+	bucket := bucketFor(lead)
+	lc := strings.ToLower(lang)
+	if _, ok := templates[lc]; !ok {
+		lc = "de"
+	}
+	t := lookup(lc, eventType, audience, bucket)
+	subject = substitute(t.Subject, lead, v)
+	body = substitute(t.Body, lead, v)
+	return subject, body
+}
+
+func bucketFor(lead int) string {
+	switch {
+	case lead <= 0:
+		return "today"
+	case lead == 1:
+		return "tomorrow"
+	default:
+		return "days"
+	}
+}
+
+// lookup walks the templates map applying the (lang → de) and
+// (event_type → andere) fallbacks. The bucket is guaranteed to exist for
+// every audience because we always define today/tomorrow/days in the de
+// baseline.
+func lookup(lang, eventType, audience, bucket string) tmpl {
+	byEvent, ok := templates[lang][eventType]
+	if !ok {
+		byEvent = templates[lang]["andere"]
+	}
+	byAudience, ok := byEvent[audience]
+	if !ok {
+		byAudience = byEvent["parents"]
+	}
+	t, ok := byAudience[bucket]
+	if !ok {
+		t = byAudience["days"]
+	}
+	return t
+}
+
+func substitute(s string, lead int, v Vars) string {
+	classSuffix := ""
+	if v.ClassName != "" {
+		classSuffix = " (" + v.ClassName + ")"
+	}
+	repl := strings.NewReplacer(
+		"{{title}}", v.Title,
+		"{{date}}", v.Date,
+		"{{date_pretty}}", v.DatePretty,
+		"{{class_name}}", v.ClassName,
+		"{{class_suffix}}", classSuffix,
+		"{{teacher_name}}", v.TeacherName,
+		"{{lead}}", fmt.Sprintf("%d", lead),
+	)
+	return repl.Replace(s)
+}
+
+type tmpl struct {
+	Subject string
+	Body    string
+}
+
+// templates[lang][eventType][audience][bucket] → tmpl
+//
+// Only the eight parent languages we ship subject-i18n.ts for are covered.
+// Custom event_types fall back to the "andere" branch. Custom languages
+// fall back to "de". This keeps the file under 500 LOC; if more locales
+// are needed, split into one file per language.
+var templates = map[string]map[string]map[string]map[string]tmpl{
+	"de": deTemplates(),
+	"en": enTemplates(),
+	"tr": trTemplates(),
+	"ar": arTemplates(),
+	"uk": ukTemplates(),
+	"ru": ruTemplates(),
+	"pl": plTemplates(),
+	"fr": frTemplates(),
+}
+
+func deTemplates() map[string]map[string]map[string]tmpl {
+	// All event types share the same template family; we only vary by audience
+	// and bucket. Specialise where wording really differs (e.g. fortbildung
+	// is school-free, schulfeier invites attendance).
+	parentToday := tmpl{
+		Subject: "Heute: {{title}}{{class_suffix}}",
+		Body:    "Liebe Eltern, heute findet {{title}} statt{{class_suffix}}. Datum: {{date_pretty}}.",
+	}
+	parentTomorrow := tmpl{
+		Subject: "Morgen: {{title}}{{class_suffix}}",
+		Body:    "Liebe Eltern, morgen ({{date_pretty}}) findet {{title}} statt{{class_suffix}}.",
+	}
+	parentDays := tmpl{
+		Subject: "In {{lead}} Tagen: {{title}}{{class_suffix}}",
+		Body:    "Liebe Eltern, in {{lead}} Tagen ({{date_pretty}}) findet {{title}} statt{{class_suffix}}.",
+	}
+	studentToday := tmpl{
+		Subject: "Heute: {{title}}",
+		Body:    "Heute ist {{title}}{{class_suffix}}.",
+	}
+	studentTomorrow := tmpl{
+		Subject: "Morgen: {{title}}",
+		Body:    "Morgen ({{date_pretty}}) ist {{title}}{{class_suffix}}.",
+	}
+	studentDays := tmpl{
+		Subject: "In {{lead}} Tagen: {{title}}",
+		Body:    "In {{lead}} Tagen ({{date_pretty}}) ist {{title}}{{class_suffix}}.",
+	}
+	bucket := func(today, tomorrow, days tmpl) map[string]tmpl {
+		return map[string]tmpl{"today": today, "tomorrow": tomorrow, "days": days}
+	}
+	universal := map[string]map[string]tmpl{
+		"parents":  bucket(parentToday, parentTomorrow, parentDays),
+		"students": bucket(studentToday, studentTomorrow, studentDays),
+	}
+	return map[string]map[string]map[string]tmpl{
+		"fortbildung":  universal,
+		"schulfeier":   universal,
+		"klassenfahrt": universal,
+		"projekttag":   universal,
+		"eltern_info":  universal,
+		"andere":       universal,
+	}
+}
+
+// The non-DE templates use the same structure; only the strings change.
+// Defined in a single helper that takes the translation map and reuses the
+// DE family glue.
+
+func makeFamily(
+	pT, pTm, pD, sT, sTm, sD tmpl,
+) map[string]map[string]map[string]tmpl {
+	bucket := func(today, tomorrow, days tmpl) map[string]tmpl {
+		return map[string]tmpl{"today": today, "tomorrow": tomorrow, "days": days}
+	}
+	universal := map[string]map[string]tmpl{
+		"parents":  bucket(pT, pTm, pD),
+		"students": bucket(sT, sTm, sD),
+	}
+	return map[string]map[string]map[string]tmpl{
+		"fortbildung":  universal,
+		"schulfeier":   universal,
+		"klassenfahrt": universal,
+		"projekttag":   universal,
+		"eltern_info":  universal,
+		"andere":       universal,
+	}
+}
+
+func enTemplates() map[string]map[string]map[string]tmpl {
+	return makeFamily(
+		tmpl{"Today: {{title}}{{class_suffix}}", "Dear parents, today {{title}} takes place{{class_suffix}}. Date: {{date_pretty}}."},
+		tmpl{"Tomorrow: {{title}}{{class_suffix}}", "Dear parents, tomorrow ({{date_pretty}}) {{title}} takes place{{class_suffix}}."},
+		tmpl{"In {{lead}} days: {{title}}{{class_suffix}}", "Dear parents, in {{lead}} days ({{date_pretty}}) {{title}} takes place{{class_suffix}}."},
+		tmpl{"Today: {{title}}", "Today is {{title}}{{class_suffix}}."},
+		tmpl{"Tomorrow: {{title}}", "Tomorrow ({{date_pretty}}) is {{title}}{{class_suffix}}."},
+		tmpl{"In {{lead}} days: {{title}}", "In {{lead}} days ({{date_pretty}}) is {{title}}{{class_suffix}}."},
+	)
+}
+
+func trTemplates() map[string]map[string]map[string]tmpl {
+	return makeFamily(
+		tmpl{"Bugün: {{title}}{{class_suffix}}", "Sayın veliler, bugün {{title}} gerçekleşiyor{{class_suffix}}. Tarih: {{date_pretty}}."},
+		tmpl{"Yarın: {{title}}{{class_suffix}}", "Sayın veliler, yarın ({{date_pretty}}) {{title}} gerçekleşiyor{{class_suffix}}."},
+		tmpl{"{{lead}} gün sonra: {{title}}{{class_suffix}}", "Sayın veliler, {{lead}} gün sonra ({{date_pretty}}) {{title}} gerçekleşiyor{{class_suffix}}."},
+		tmpl{"Bugün: {{title}}", "Bugün {{title}}{{class_suffix}}."},
+		tmpl{"Yarın: {{title}}", "Yarın ({{date_pretty}}) {{title}}{{class_suffix}}."},
+		tmpl{"{{lead}} gün sonra: {{title}}", "{{lead}} gün sonra ({{date_pretty}}) {{title}}{{class_suffix}}."},
+	)
+}
+
+func arTemplates() map[string]map[string]map[string]tmpl {
+	return makeFamily(
+		tmpl{"اليوم: {{title}}{{class_suffix}}", "أعزائي أولياء الأمور، اليوم يقام {{title}}{{class_suffix}}. التاريخ: {{date_pretty}}."},
+		tmpl{"غدًا: {{title}}{{class_suffix}}", "أعزائي أولياء الأمور، غدًا ({{date_pretty}}) يقام {{title}}{{class_suffix}}."},
+		tmpl{"بعد {{lead}} أيام: {{title}}{{class_suffix}}", "أعزائي أولياء الأمور، بعد {{lead}} أيام ({{date_pretty}}) يقام {{title}}{{class_suffix}}."},
+		tmpl{"اليوم: {{title}}", "اليوم {{title}}{{class_suffix}}."},
+		tmpl{"غدًا: {{title}}", "غدًا ({{date_pretty}}) {{title}}{{class_suffix}}."},
+		tmpl{"بعد {{lead}} أيام: {{title}}", "بعد {{lead}} أيام ({{date_pretty}}) {{title}}{{class_suffix}}."},
+	)
+}
+
+func ukTemplates() map[string]map[string]map[string]tmpl {
+	return makeFamily(
+		tmpl{"Сьогодні: {{title}}{{class_suffix}}", "Шановні батьки, сьогодні відбудеться {{title}}{{class_suffix}}. Дата: {{date_pretty}}."},
+		tmpl{"Завтра: {{title}}{{class_suffix}}", "Шановні батьки, завтра ({{date_pretty}}) відбудеться {{title}}{{class_suffix}}."},
+		tmpl{"Через {{lead}} днів: {{title}}{{class_suffix}}", "Шановні батьки, через {{lead}} днів ({{date_pretty}}) відбудеться {{title}}{{class_suffix}}."},
+		tmpl{"Сьогодні: {{title}}", "Сьогодні {{title}}{{class_suffix}}."},
+		tmpl{"Завтра: {{title}}", "Завтра ({{date_pretty}}) {{title}}{{class_suffix}}."},
+		tmpl{"Через {{lead}} днів: {{title}}", "Через {{lead}} днів ({{date_pretty}}) {{title}}{{class_suffix}}."},
+	)
+}
+
+func ruTemplates() map[string]map[string]map[string]tmpl {
+	return makeFamily(
+		tmpl{"Сегодня: {{title}}{{class_suffix}}", "Уважаемые родители, сегодня состоится {{title}}{{class_suffix}}. Дата: {{date_pretty}}."},
+		tmpl{"Завтра: {{title}}{{class_suffix}}", "Уважаемые родители, завтра ({{date_pretty}}) состоится {{title}}{{class_suffix}}."},
+		tmpl{"Через {{lead}} дней: {{title}}{{class_suffix}}", "Уважаемые родители, через {{lead}} дней ({{date_pretty}}) состоится {{title}}{{class_suffix}}."},
+		tmpl{"Сегодня: {{title}}", "Сегодня {{title}}{{class_suffix}}."},
+		tmpl{"Завтра: {{title}}", "Завтра ({{date_pretty}}) {{title}}{{class_suffix}}."},
+		tmpl{"Через {{lead}} дней: {{title}}", "Через {{lead}} дней ({{date_pretty}}) {{title}}{{class_suffix}}."},
+	)
+}
+
+func plTemplates() map[string]map[string]map[string]tmpl {
+	return makeFamily(
+		tmpl{"Dzisiaj: {{title}}{{class_suffix}}", "Drodzy rodzice, dzisiaj odbywa się {{title}}{{class_suffix}}. Data: {{date_pretty}}."},
+		tmpl{"Jutro: {{title}}{{class_suffix}}", "Drodzy rodzice, jutro ({{date_pretty}}) odbywa się {{title}}{{class_suffix}}."},
+		tmpl{"Za {{lead}} dni: {{title}}{{class_suffix}}", "Drodzy rodzice, za {{lead}} dni ({{date_pretty}}) odbywa się {{title}}{{class_suffix}}."},
+		tmpl{"Dzisiaj: {{title}}", "Dzisiaj {{title}}{{class_suffix}}."},
+		tmpl{"Jutro: {{title}}", "Jutro ({{date_pretty}}) {{title}}{{class_suffix}}."},
+		tmpl{"Za {{lead}} dni: {{title}}", "Za {{lead}} dni ({{date_pretty}}) {{title}}{{class_suffix}}."},
+	)
+}
+
+func frTemplates() map[string]map[string]map[string]tmpl {
+	return makeFamily(
+		tmpl{"Aujourd'hui : {{title}}{{class_suffix}}", "Chers parents, aujourd'hui a lieu {{title}}{{class_suffix}}. Date : {{date_pretty}}."},
+		tmpl{"Demain : {{title}}{{class_suffix}}", "Chers parents, demain ({{date_pretty}}) a lieu {{title}}{{class_suffix}}."},
+		tmpl{"Dans {{lead}} jours : {{title}}{{class_suffix}}", "Chers parents, dans {{lead}} jours ({{date_pretty}}) a lieu {{title}}{{class_suffix}}."},
+		tmpl{"Aujourd'hui : {{title}}", "Aujourd'hui c'est {{title}}{{class_suffix}}."},
+		tmpl{"Demain : {{title}}", "Demain ({{date_pretty}}) c'est {{title}}{{class_suffix}}."},
+		tmpl{"Dans {{lead}} jours : {{title}}", "Dans {{lead}} jours ({{date_pretty}}) c'est {{title}}{{class_suffix}}."},
+	)
+}