Restructure: Move 43 files into 8 domain packages (backend-lehrer)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

backend-lehrer/unit_analytics_api.py

@@ -1,25 +1,4 @@
-"""
-Breakpilot Drive - Unit Analytics API — Barrel Re-export.
-
-Erweiterte Analytics fuer Lernfortschritt:
-- Pre/Post Gain Visualisierung
-- Misconception-Tracking
-- Stop-Level Analytics
-- Aggregierte Klassen-Statistiken
-- Export-Funktionen
-
-Split into:
-  - unit_analytics_models.py: Pydantic models & enums
-  - unit_analytics_helpers.py: Database access & computation helpers
-  - unit_analytics_routes.py: Core analytics endpoint handlers
-  - unit_analytics_export.py: Export & dashboard endpoints
-"""
-
-from fastapi import APIRouter
-
-from unit_analytics_routes import router as _routes_router
-from unit_analytics_export import router as _export_router
-
-router = APIRouter(prefix="/api/analytics", tags=["Unit Analytics"])
-router.include_router(_routes_router)
-router.include_router(_export_router)
+# Backward-compat shim -- module moved to units/analytics_api.py
+import importlib as _importlib
+import sys as _sys
+_sys.modules[__name__] = _importlib.import_module("units.analytics_api")