fix: resolve 6 Gitea issues (#9, #10, #12, #14, #15, #21)

- #21: Add missing await in removeChoiceIfPresent() to prevent user appearing in two restaurants
- #15: Add 1-hour TTL for menu refetching to avoid scraping on every page load
- #9: Block stats API and UI navigation for future dates
- #14: Add restaurant warnings (missing soup/prices, stale data) with warning icon
- #12: Pre-fill restaurant/departure dropdowns from existing choices on page refresh
- #10: Add voting statistics endpoint and table on stats page

server/src/service.ts

@@ -198,7 +198,14 @@ export async function getRestaurantMenu(restaurant: Restaurant, date?: Date, for
             food: [],
         };
     }
-    if (forceRefresh || (!weekMenu[dayOfWeekIndex][restaurant]?.food?.length && !weekMenu[dayOfWeekIndex][restaurant]?.closed)) {
+    const MENU_REFETCH_TTL_MS = 60 * 60 * 1000; // 1 hour
+    const existingMenu = weekMenu[dayOfWeekIndex][restaurant];
+    const lastFetchExpired = !existingMenu?.lastUpdate ||
+        existingMenu.lastUpdate === now || // freshly initialized, never fetched
+        (now - existingMenu.lastUpdate) > MENU_REFETCH_TTL_MS;
+    const shouldFetch = forceRefresh ||
+        (!existingMenu?.food?.length && !existingMenu?.closed && lastFetchExpired);
+    if (shouldFetch) {
         const firstDay = getFirstWorkDayOfWeek(usedDate);
         
         try {
@@ -240,7 +247,32 @@ export async function getRestaurantMenu(restaurant: Restaurant, date?: Date, for
             console.error(`Selhalo načtení jídel pro podnik ${restaurant}`, e);
         }
     }
-    return weekMenu[dayOfWeekIndex][restaurant]!;
+    const result = weekMenu[dayOfWeekIndex][restaurant]!;
+    result.warnings = generateMenuWarnings(result, now);
+    return result;
+}
+
+/**
+ * Generuje varování o kvalitě/úplnosti dat menu restaurace.
+ */
+function generateMenuWarnings(menu: RestaurantDayMenu, now: number): string[] {
+    const warnings: string[] = [];
+    if (!menu.food?.length || menu.closed) {
+        return warnings;
+    }
+    const hasSoup = menu.food.some(f => f.isSoup);
+    if (!hasSoup) {
+        warnings.push('Chybí polévka');
+    }
+    const missingPrice = menu.food.some(f => !f.isSoup && (!f.price || f.price.trim() === ''));
+    if (missingPrice) {
+        warnings.push('U některých jídel chybí cena');
+    }
+    const STALE_THRESHOLD_MS = 24 * 60 * 60 * 1000;
+    if (menu.lastUpdate && (now - menu.lastUpdate) > STALE_THRESHOLD_MS) {
+        warnings.push('Data jsou starší než 24 hodin');
+    }
+    return warnings;
 }
 
 /**
@@ -378,7 +410,7 @@ export async function addChoice(login: string, trusted: boolean, locationKey: Lu
         data = await removeChoiceIfPresent(login, usedDate);
     } else {
         // Mažeme případné ostatní volby (měla by být maximálně jedna)
-        removeChoiceIfPresent(login, usedDate, locationKey);
+        data = await removeChoiceIfPresent(login, usedDate, locationKey);
     }
     // TODO vytáhnout inicializaci "prázdné struktury" do vlastní funkce
     data.choices[locationKey] ??= {};