fix: dark mode event colors, sidebar height, calendar default, photo badge

- event-config: all bgClass/borderClass get dark:bg-*-950/50 + dark:border-*-800 variants — fixes bright pastel backgrounds in dark mode
- nav: h-screen → h-[100dvh] — fixes sidebar bottom buttons hidden behind mobile browser chrome
- calendar: selectedDay defaults to today, never null — events shown immediately on load
- timeline + dashboard: photo indicator (ImageIcon) on events with metadata.photo

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

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

@@ -8,7 +8,7 @@ import { EventIcon } from "@/components/event-icon";
 import { useBaby } from "@/contexts/baby-context";
 import { format, isToday, isYesterday } from "date-fns";
 import { fr } from "date-fns/locale";
-import { Trash2, StickyNote, Pencil, CheckSquare, Square, XCircle } from "lucide-react";
+import { Trash2, StickyNote, Pencil, CheckSquare, Square, XCircle, ImageIcon } from "lucide-react";
 import Image from "next/image";
 import { EventModal } from "@/components/event-modal";
 
@@ -271,6 +271,9 @@ export default function TimelinePage() {
                         {summary && <span className="text-xs text-slate-400 dark:text-slate-500 ml-2">{summary}</span>}
                         {ev.notes && <p className="text-xs text-slate-400 dark:text-slate-500 truncate mt-0.5 italic">{ev.notes}</p>}
                       </div>
+                      {typeof ev.metadata?.photo === "string" && ev.metadata.photo && (
+                        <ImageIcon className="w-3.5 h-3.5 text-slate-400 dark:text-slate-500 flex-shrink-0" />
+                      )}
                       <span className="text-xs text-slate-400 dark:text-slate-500 flex-shrink-0 font-mono">
                         {format(new Date(ev.startedAt), "HH:mm")}
                       </span>