fix: disallow selecting dates in the past or today

appsettings.json

@@ -1,17 +1,22 @@
 {
   "activities": [
     { "name": "Essen bei Namaste", "icon": "🍛", "type": "short" },
-    { "name": "Kinofilm", "icon": "🎬", "type": "long" },
+    { "name": "Ins Kino", "icon": "🎬", "type": "short" },
     { "name": "Film zu Hause + Essen bestellen", "icon": "🛋️", "type": "long" },
     { "name": "Spaziergang im Wald", "icon": "🌲", "type": "short" },
     { "name": "Museum für Gegenwartskunst", "icon": "🖼️", "type": "long" },
     { "name": "Picknick auf der Wiese", "icon": "🧺", "type": "short" },
-    { "name": "Massage zu Hause", "icon": "💆", "type": "short" }
+    { "name": "Massage zu Hause", "icon": "💆", "type": "short" },
+    { "name": "Ausgedehnte Wanderung", "icon": "🥾", "type": "long" }
   ],
   "availableDates": [
-    { "date": "2026-08-15", "type": "long" },
-    { "date": "2026-08-16", "type": "short" },
+    { "date": "2026-08-11", "type": "short" },
+    { "date": "2026-08-15", "type": "short" },
+    { "date": "2026-08-18", "type": "short" },
+    { "date": "2026-08-20", "type": "short" },
+    { "date": "2026-08-22", "type": "long" },
     { "date": "2026-08-23", "type": "long" },
+
     { "date": "2026-08-30", "type": "short" },
     { "date": "2026-09-05", "type": "long" },
     { "date": "2026-09-06", "type": "short" }

datetime.js

@@ -50,7 +50,7 @@
 
       const upcoming = Array.from(availableDatesMap.keys())
         .map((dateKey) => new Date(`${dateKey}T00:00:00`))
-        .filter((date) => date >= today)
+        .filter((date) => date > today)
         .sort((a, b) => a - b);
 
       if (upcoming.length > 0) {
@@ -88,7 +88,8 @@
       button.textContent = String(day);
 
       const dateInfo = availableDatesMap.get(key);
-      const isAvailable = Boolean(dateInfo);
+      const isPastOrToday = cellDate <= today;
+      const isAvailable = Boolean(dateInfo) && !isPastOrToday;
       const isToday = cellDate.getTime() === today.getTime();
       const isSelected = selectedDate && cellDate.getTime() === selectedDate.getTime();