fix: use osascript for folder picker on macOS

server.py

@@ -46,13 +46,12 @@ def serve_frontend():
 
 @app.get("/pick-folder")
 def pick_folder():
-    import tkinter as tk
-    from tkinter import filedialog
-    root = tk.Tk()
-    root.withdraw()
-    root.attributes("-topmost", True)
-    folder = filedialog.askdirectory(title="Ordner auswählen")
-    root.destroy()
+    import subprocess
+    result = subprocess.run(
+        ["osascript", "-e", 'POSIX path of (choose folder with prompt "Ordner auswählen")'],
+        capture_output=True, text=True
+    )
+    folder = result.stdout.strip().rstrip("/")
     if not folder:
         raise HTTPException(status_code=204, detail="Kein Ordner ausgewählt")
     return {"folder": folder}