Translate Python log messages + fix rhinopanel import in PROJECTS

- startup.py: all user-visible messages translated to English
- panel_base.py: icon/rendering log messages translated
- toolbar.py: display mode check messages translated
- Global: Panel registered/opened/listener-active across all modules
- Fix: elemente.py and other files with stale 'import rhinopanel'
  were missing from PROJECTS sync — now properly copied

rhino/schnitte.py

@@ -593,7 +593,7 @@ def install_double_click_handler():
         h = _SchnittDoubleClickHandler()
         h.Enabled = True
         sc.sticky["_dossier_schnitt_dblclick_handler"] = h
-        print("[SCHNITT] Doppelklick-Handler aktiv")
+        print("[SCHNITT] Double-click handler active")
     except Exception as ex:
         print("[SCHNITT] install_double_click_handler:", ex)