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/startup.py

@@ -44,13 +44,13 @@ _UI_FILE = os.path.join(_HERE, "DOSSIERUI.rhw")
 # Muss synchron sein mit launcher/modules.json. Wenn neue Module dazukommen,
 # beide Stellen pflegen.
 _MODULE_TO_PY = {
-    "ebenen":      "rhinopanel",
-    "oberleiste":  "oberleiste",
+    "ebenen":      "layers_panel",
+    "oberleiste":  "toolbar",
     "ausschnitte": "ausschnitte",
-    "gestaltung":  "gestaltung",
-    "werkzeuge":   "werkzeuge",
+    "gestaltung":  "styles",
+    "werkzeuge":   "tools",
     "overrides":   "overrides_panel",
-    "dimensionen": "dimensionen",
+    "dimensionen": "dimensions",
     "layouts":     "layouts",
     "elemente":    "elemente",
 }
@@ -209,7 +209,7 @@ def _check_doc_unit(doc):
             return
     except Exception: pass
     try:
-        import rhinopanel
+        import layers_panel as rhinopanel
         target_unit_str  = rhinopanel.get_project_unit(doc)
         target_unit_enum = rhinopanel.get_project_unit_enum(doc)
     except Exception as ex: