feat: maintenance banner, activities log, pinned note, event templates, weekly summary cron

Maintenance mode banner:
- App layout reads SystemConfig maintenance_mode at server render time
- Amber sticky banner for regular users, dimmed indicator for superadmin

Baby activities (3 new event types):
- BATH (Bath icon, sky, timer+duration)
- WALK / Balade (Footprints icon, lime)
- TUMMY_TIME (Baby icon, amber)
- Added to EventType enum, EVENT_CONFIG, event-icon.tsx, dashboard quick-log

Pinned family note:
- Shared across all family members, shown at top of dashboard
- Inline edit with author + timestamp; /api/family/pinned-note GET/PATCH
- pinnedNote + pinnedNoteUpdatedAt + pinnedNoteAuthor fields on Family model

Event templates:
- Named quick-log presets per family (type + label + metadata)
- Dashboard row: tap to open pre-filled EventModal; hover ✕ to delete
- Dropdown to create new template; /api/event-templates GET/POST + /[id] PATCH/DELETE
- EventTemplate model in schema

Weekly summary cron:
- POST /api/cron/weekly-summary — auth via Bearer cron_secret (SystemConfig or env)
- Per family, per baby: feeds count, sleep total+avg, diaper count, latest weight
- Sends Pushover to all family members with pushoverUserKey
- Optional body.familyId to target one family

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

prisma/schema.prisma

@@ -85,12 +85,27 @@ model VerificationToken {
 }
 
 model Family {
-  id         String   @id @default(cuid())
-  name       String
-  inviteCode String   @unique @default(cuid())
-  users      User[]
-  babies     Baby[]
-  createdAt  DateTime @default(now())
+  id                   String          @id @default(cuid())
+  name                 String
+  inviteCode           String          @unique @default(cuid())
+  users                User[]
+  babies               Baby[]
+  eventTemplates       EventTemplate[]
+  pinnedNote           String?
+  pinnedNoteUpdatedAt  DateTime?
+  pinnedNoteAuthor     String?
+  createdAt            DateTime        @default(now())
+}
+
+model EventTemplate {
+  id        String    @id @default(cuid())
+  familyId  String
+  family    Family    @relation(fields: [familyId], references: [id], onDelete: Cascade)
+  label     String
+  type      EventType
+  metadata  Json?
+  sortOrder Int       @default(0)
+  createdAt DateTime  @default(now())
 }
 
 model Baby {
@@ -136,6 +151,9 @@ enum EventType {
   NIGHT_SLEEP
   MEDICATION
   TEMPERATURE
+  BATH
+  WALK
+  TUMMY_TIME
 }
 
 model GrowthLog {