i18n DE/EN + DossierSettings panel + English file renames

i18n:
- src/i18n/de.json + en.json: 200+ keys covering all main panels
- src/i18n/index.js: t(key, vars) reads window.DOSSIER_LANG
- panel_base.py: injects window.DOSSIER_LANG from dossier_settings.json
- EbenenManager, GeschossManager, AusschnitteApp, LayoutsApp: all
  context menus and main labels use t()

DossierSettings panel:
- DossierSettingsApp.jsx: language toggle (DE/EN pill) + launcher status
- toolbar.py: OPEN_SETTINGS opens new Rhino-hosted satellite window,
  SAVE_LANG writes lang to dossier_settings.json + reloads all panels

File renames (JSX → English):
- ZeichnungsebenenApp → DrawingLevelsApp
- GeschossManager/Dialog/Settings → Floor*
- AusschnitteApp/Settings → Viewports*
- EbenenManager/Settings → Layer*
- GestaltungApp → StylesApp, OberleisteApp → ToolbarApp
- WerkzeugeApp → ToolsApp, DimensionenApp → DimensionsApp
- MassstabApp → ScaleApp, KameraApp → CameraApp
- MasseSettingsApp → UnitsSettingsApp
- ConfirmDeleteEbene → ConfirmDeleteLayer
- AusschnittLayerDialog → ViewportLayerDialog

Python module renames:
- rhinopanel.py → layers_panel.py
- oberleiste.py → toolbar.py
- gestaltung.py → styles.py
- werkzeuge.py → tools.py
- dimensionen.py → dimensions.py
- startup.py _MODULE_TO_PY updated, all cross-imports fixed

rhino/aliases/cmd/section.py

@@ -20,7 +20,7 @@ else:
             "cutAtLine": True, "namePrefix": "S",
         }
         try:
-            import rhinopanel
+            import layers_panel as rhinopanel
             ps = rhinopanel.load_project_settings(doc)
             d = (ps or {}).get("defaults", {})
             defaults["depthBack"] = float(d.get("schnittDepthBack", 8.0))

rhino/aliases/cmd/smart_join.py

@@ -392,7 +392,7 @@ def _run():
     # gestaltung fuer Fill-Re-Apply
     _g = None
     try:
-        import gestaltung as _gmod; _g = _gmod
+        import styles as _gmod; _g = _gmod
     except Exception as iex:
         print("[SMART-JOIN] gestaltung import:", iex)
 

rhino/aliases/cmd/smart_split.py

@@ -233,7 +233,7 @@ def _run():
                             _replicate_hatch(doc, nobj, hatch_props)
                 else:
                     try:
-                        import gestaltung as _gmod
+                        import styles as _gmod
                         for nid in new_ids:
                             nobj = doc.Objects.FindId(nid)
                             if nobj is not None: