fix: Blanko-Build-Fehler (data-Verzeichnis + users-Schema) und publish-win ignorieren

- Program.cs: Directory.CreateDirectory(dataDir) vor DB-Zugriff
- DatabaseService: is_admin, persona, settings, default_path ins CREATE TABLE users
- .gitignore + gott.csproj: publish-win/ ausschließen

Services/DatabaseService.cs

@@ -207,6 +207,10 @@ public class DatabaseService
                 username      TEXT NOT NULL UNIQUE COLLATE NOCASE,
                 password_hash TEXT NOT NULL,
                 display_name  TEXT,
+                is_admin      INTEGER NOT NULL DEFAULT 0,
+                persona       TEXT,
+                settings      TEXT,
+                default_path  TEXT,
                 created_at    TEXT NOT NULL,
                 updated_at    TEXT NOT NULL
             );