feat(ui): constrain decimal input and add stacked timed toasts with uniform actions

src/Duempelkas.Desktop/Program.cs

@@ -27,6 +27,16 @@ class Program
         var appDataDir = Path.Combine(
             Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData),
             "Duempelkas");
+        var isolated = false;
+#if DEBUG
+        var directoryIndex = Array.IndexOf(args, "--data-directory");
+        if (directoryIndex >= 0)
+        {
+            if (directoryIndex + 1 >= args.Length) throw new ArgumentException("Datenordner fehlt.");
+            appDataDir = Path.GetFullPath(args[directoryIndex + 1]);
+            isolated = true;
+        }
+#endif
         Directory.CreateDirectory(appDataDir);
 
         var dbPath = Path.Combine(appDataDir, "duempelkas.db");
@@ -34,7 +44,7 @@ class Program
         // One-time compatibility: keep existing data if older versions stored DB next to the app executable.
         var legacyExeDirectory = Path.GetDirectoryName(Environment.ProcessPath ?? AppContext.BaseDirectory) ?? AppContext.BaseDirectory;
         var legacyDbPath = Path.Combine(legacyExeDirectory, "duempelkas.db");
-        if (!File.Exists(dbPath) && File.Exists(legacyDbPath))
+        if (!isolated && !File.Exists(dbPath) && File.Exists(legacyDbPath))
         {
             try
             {
@@ -50,7 +60,7 @@ class Program
             }
         }
 
-        appBuilder.Services.AddInfrastructure($"Data Source={dbPath}");
+        appBuilder.Services.AddInfrastructure(new Microsoft.Data.Sqlite.SqliteConnectionStringBuilder { DataSource = dbPath }.ToString(), appDataDir);
 
         appBuilder.RootComponents.Add<Duempelkas.App.Components.App>("app");
 
@@ -72,9 +82,7 @@ class Program
         }
 
         // Load saved window size or use defaults
-        var settingsPath = Path.Combine(
-            Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData),
-            "Duempelkas", "window.json");
+        var settingsPath = Path.Combine(appDataDir, "window.json");
 
         int savedWidth = 1280, savedHeight = 800;
         if (File.Exists(settingsPath))
@@ -90,7 +98,7 @@ class Program
         }
 
         app.MainWindow
-            .SetTitle("Dümpelkas – Kassenbuch")
+            .SetTitle(isolated ? "Dümpelkas – Testdaten" : "Dümpelkas – Kassenbuch")
             .SetSize(savedWidth, savedHeight)
             .SetUseOsDefaultSize(false);