feat: sleep chart, bottle-from-stock, growth alert cron

- SleepTimeline component in stats: 7-night bar chart, 19h–11h window,
  NIGHT_SLEEP (indigo) and NAP (violet) blocks, pure CSS positioning
- Bottle modal: fetch available maternal milk lots, chip picker,
  auto-selects oldest, marks selected lot as used after save
- /api/cron/growth-alert: Bearer-auth POST, configurable threshold via
  growth_alert_days SystemConfig key (default 30 days), Pushover alert
  to all family users per baby with no recent weight log
- Admin config ALLOWED_KEYS: add cron_secret + growth_alert_days

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

src/app/(app)/stats/page.tsx

@@ -7,7 +7,7 @@ import {
   LineChart, Line, CartesianGrid,
 } from "recharts";
 import { useBaby } from "@/contexts/baby-context";
-import { format, subDays, startOfDay, endOfDay } from "date-fns";
+import { format, subDays, startOfDay, endOfDay, isToday } from "date-fns";
 import { fr } from "date-fns/locale";
 import { EventType } from "@/lib/event-config";
 
@@ -110,6 +110,80 @@ function useDarkMode() {
   return isDark;
 }
 
+function SleepTimeline({ events }: { events: Event[] }) {
+  const WIN_START_H = 19;
+  const WIN_HOURS = 16; // 19:00 → 11:00 next day
+  const WIN_MS = WIN_HOURS * 3600000;
+
+  const rows = Array.from({ length: 7 }, (_, i) => {
+    const day = startOfDay(subDays(new Date(), 6 - i));
+    const winStart = day.getTime() + WIN_START_H * 3600000;
+    const winEnd = winStart + WIN_MS;
+
+    const blocks = events
+      .filter((e) => (e.type === "NAP" || e.type === "NIGHT_SLEEP") && e.endedAt)
+      .map((e) => ({ s: new Date(e.startedAt).getTime(), en: new Date(e.endedAt!).getTime(), type: e.type }))
+      .filter((e) => e.s < winEnd && e.en > winStart)
+      .map((e) => ({
+        left: (Math.max(e.s, winStart) - winStart) / WIN_MS * 100,
+        width: (Math.min(e.en, winEnd) - Math.max(e.s, winStart)) / WIN_MS * 100,
+        isNight: e.type === "NIGHT_SLEEP",
+      }));
+
+    return {
+      label: isToday(day) ? "Auj." : format(day, "EEE d", { locale: fr }),
+      isToday: isToday(day),
+      blocks,
+    };
+  });
+
+  const markers = [20, 22, 0, 2, 4, 6, 8, 10].map((h) => ({
+    label: h === 0 ? "00h" : `${h}h`,
+    pos: ((h < WIN_START_H ? h + 24 : h) - WIN_START_H) / WIN_HOURS * 100,
+  }));
+
+  return (
+    <div className="bg-white dark:bg-slate-800 border border-slate-200 dark:border-slate-700 rounded-xl p-4 mb-4">
+      <p className="text-sm font-medium text-slate-700 dark:text-slate-200 mb-4">Nuits — 7 derniers jours</p>
+      <div className="relative h-4 ml-10 mb-0.5">
+        {markers.map((m) => (
+          <span key={m.label} className="absolute text-[9px] text-slate-400 dark:text-slate-500 -translate-x-1/2" style={{ left: `${m.pos}%` }}>
+            {m.label}
+          </span>
+        ))}
+      </div>
+      <div className="space-y-1.5 mt-1">
+        {rows.map((row, i) => (
+          <div key={i} className="flex items-center gap-2">
+            <span className={`text-[10px] w-10 flex-shrink-0 text-right font-medium ${row.isToday ? "text-indigo-600 dark:text-indigo-400" : "text-slate-400 dark:text-slate-500"}`}>
+              {row.label}
+            </span>
+            <div className="relative flex-1 h-4 bg-slate-100 dark:bg-slate-700/50 rounded-full overflow-hidden">
+              {row.blocks.map((b, j) => (
+                <div
+                  key={j}
+                  className={`absolute top-0 h-full ${b.isNight ? "bg-indigo-500 dark:bg-indigo-400" : "bg-violet-400 dark:bg-violet-500"}`}
+                  style={{ left: `${b.left}%`, width: `${Math.max(b.width, 0.8)}%` }}
+                />
+              ))}
+            </div>
+          </div>
+        ))}
+      </div>
+      <div className="flex items-center gap-4 mt-3">
+        <div className="flex items-center gap-1.5">
+          <div className="w-3 h-2 rounded-sm bg-indigo-500" />
+          <span className="text-[10px] text-slate-400 dark:text-slate-500">Nuit</span>
+        </div>
+        <div className="flex items-center gap-1.5">
+          <div className="w-3 h-2 rounded-sm bg-violet-400" />
+          <span className="text-[10px] text-slate-400 dark:text-slate-500">Sieste</span>
+        </div>
+      </div>
+    </div>
+  );
+}
+
 const DAY_OPTIONS = [7, 14, 30, 90] as const;
 type DaysOption = typeof DAY_OPTIONS[number];
 
@@ -235,6 +309,8 @@ export default function StatsPage() {
         </div>
       </div>
 
+      <SleepTimeline events={events} />
+
       {/* Feeding summary */}
       <div className="bg-white dark:bg-slate-800 border border-slate-200 dark:border-slate-700 rounded-xl p-4 mb-4">
         <p className="text-sm font-medium text-slate-700 dark:text-slate-200 mb-3">Résumé des repas</p>