reworked developer tools with diagnostics, storage viewers and release-capable debug overlays

lib/storage/dev_tools_settings.dart

@@ -8,8 +8,22 @@ enum MarianumConnectEndpoint { live, beta, custom }
 @JsonSerializable()
 class DevToolsSettings {
   bool showPerformanceOverlay;
-  bool checkerboardOffscreenLayers;
-  bool checkerboardRasterCacheImages;
+
+  @JsonKey(defaultValue: false)
+  bool showFrameStats;
+
+  @JsonKey(defaultValue: false)
+  bool showMemoryStats;
+
+  @JsonKey(defaultValue: false)
+  bool showSemanticsDebugger;
+
+  @JsonKey(defaultValue: false)
+  bool slowAnimations;
+
+  /// Forced text scale factor; `0` follows the system setting.
+  @JsonKey(defaultValue: 0)
+  double textScaleOverride;
 
   @JsonKey(defaultValue: MarianumConnectEndpoint.live)
   MarianumConnectEndpoint marianumConnectEndpoint;
@@ -24,8 +38,11 @@ class DevToolsSettings {
 
   DevToolsSettings({
     required this.showPerformanceOverlay,
-    required this.checkerboardOffscreenLayers,
-    required this.checkerboardRasterCacheImages,
+    this.showFrameStats = false,
+    this.showMemoryStats = false,
+    this.showSemanticsDebugger = false,
+    this.slowAnimations = false,
+    this.textScaleOverride = 0,
     this.marianumConnectEndpoint = MarianumConnectEndpoint.live,
     this.marianumConnectCustomUrl = '',
     this.emergencyNoticeUrl = '',
@@ -51,7 +68,8 @@ class DevToolsSettings {
 
   /// Compiled-in source for the backend-independent emergency notice. Must live
   /// on infrastructure that is reachable even when MarianumConnect is down.
-  static const String emergencyNoticeDefaultUrl = 'https://www.marianum-fulda.de/~aushang/marMobile.override';
+  static const String emergencyNoticeDefaultUrl =
+      'https://www.marianum-fulda.de/~aushang/marMobile.override';
 
   String? resolveEmergencyNoticeUrl() =>
       sanitizeCustomUrl(emergencyNoticeUrl) ??