added empty logbook state

lib/l10n/intl_de.arb

@@ -174,5 +174,6 @@
     "notSet": "Nicht gesetzt",
     "location": "Standort",
     "noMapsAppFound": "Keine Kartenanwendung gefunden.",
-    "logbook": "Fototagebuch"
+    "logbook": "Fototagebuch",
+    "noPhotos": "Keine Fotos"
 }

lib/l10n/intl_en.arb

@@ -174,5 +174,6 @@
     "notSet": "Not set",
     "location": "Location",
     "noMapsAppFound": "No maps application found.",
-    "logbook": "Logbook"
+    "logbook": "Logbook",
+    "noPhotos": "No photos"
 }

lib/l10n/intl_fr.arb

@@ -165,5 +165,6 @@
     "notSet": "Non défini",
     "location": "Emplacement",
     "noMapsAppFound": "Aucune application de cartes trouvée.",
-    "logbook": "Carnet photo"
+    "logbook": "Carnet photo",
+    "noPhotos": "Aucune photo"
 }

lib/l10n/intl_ru.arb

@@ -164,5 +164,6 @@
     "notSet": "Не задано",
     "location": "Местоположение",
     "noMapsAppFound": "Приложение карт не найдено.",
-    "logbook": "Фотожурнал"
+    "logbook": "Фотожурнал",
+    "noPhotos": "Нет фотографий"
 }

lib/l10n/intl_zh.arb

@@ -162,5 +162,6 @@
     "notSet": "未设置",
     "location": "位置",
     "noMapsAppFound": "未找到地图应用程序。",
-    "logbook": "拍照日志"
+    "logbook": "拍照日志",
+    "noPhotos": "没有照片"
 }

lib/screens/logbook/screen_logbook.dart

@@ -6,6 +6,7 @@ import 'package:lightmeter/providers/logbook_photos_provider.dart';
 import 'package:lightmeter/res/dimens.dart';
 import 'package:lightmeter/screens/logbook/components/grid_tile/widget_grid_tile_logbook_photo.dart';
 import 'package:lightmeter/screens/shared/sliver_screen/screen_sliver.dart';
+import 'package:lightmeter/screens/shared/icon_placeholder/widget_icon_placeholder.dart';
 import 'package:m3_lightmeter_resources/m3_lightmeter_resources.dart';
 
 class LogbookScreen extends StatefulWidget {
@@ -53,6 +54,17 @@ class _PicturesGridBuilder extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
+    if (values.isEmpty) {
+      return SliverFillRemaining(
+        hasScrollBody: false,
+        child: Center(
+          child: IconPlaceholder(
+            icon: Icons.photo_outlined,
+            text: S.of(context).noPhotos,
+          ),
+        ),
+      );
+    }
     return SliverPadding(
       padding: const EdgeInsets.symmetric(horizontal: Dimens.paddingM),
       sliver: SliverGrid(