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>

src/app/(app)/layout.tsx

@@ -3,16 +3,42 @@ import { redirect } from "next/navigation";
 import { SidebarNav, BottomNav } from "@/components/nav";
 import { BabyProvider } from "@/contexts/baby-context";
 import { QuickAddFab } from "@/components/quick-add-fab";
+import { prisma } from "@/lib/prisma";
+import { AlertTriangle } from "lucide-react";
+
+async function getMaintenanceMode(): Promise<boolean> {
+  try {
+    const row = await prisma.systemConfig.findUnique({ where: { key: "maintenance_mode" } });
+    return row?.value === "true";
+  } catch {
+    return false;
+  }
+}
 
 export default async function AppLayout({ children }: { children: React.ReactNode }) {
   const session = await auth();
   if (!session?.user) redirect("/auth/login");
 
+  const maintenance = await getMaintenanceMode();
+  const isSuperAdmin = (session.user as { isSuperAdmin?: boolean })?.isSuperAdmin;
+
   return (
     <BabyProvider>
       <div className="min-h-screen bg-slate-50 dark:bg-slate-900">
+        {maintenance && (
+          <div className={`fixed top-0 left-0 right-0 z-[100] px-4 py-2.5 flex items-center gap-2 justify-center text-sm font-medium shadow-md ${
+            isSuperAdmin
+              ? "bg-amber-400/90 text-amber-900 text-xs py-1.5"
+              : "bg-amber-500 text-white"
+          }`}>
+            <AlertTriangle className="w-4 h-4 flex-shrink-0" />
+            {isSuperAdmin
+              ? "Mode maintenance actif (visible des utilisateurs)"
+              : "Maintenance en cours — certaines fonctionnalités peuvent être indisponibles"}
+          </div>
+        )}
         <SidebarNav />
-        <main className="app-main min-h-screen">
+        <main className={`app-main min-h-screen${maintenance ? " pt-10" : ""}`}>
           {children}
         </main>
         <BottomNav />