Restructure: Move 52 files into 7 domain packages

korrektur/ zeugnis/ admin/ compliance/ worksheet/ training/ metrics/
52 shims, relative imports, RAG untouched.

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

klausur-service/backend/nru_worksheet_generator.py

@@ -1,26 +1,4 @@
-"""
-NRU Worksheet Generator — barrel re-export.
-
-All implementation split into:
-  nru_worksheet_models — data classes, entry separation
-  nru_worksheet_html   — HTML generation
-  nru_worksheet_pdf    — PDF generation
-
-Per scanned page, we generate 2 worksheet pages.
-"""
-
-# Models
-from nru_worksheet_models import (  # noqa: F401
-    VocabEntry,
-    SentenceEntry,
-    separate_vocab_and_sentences,
-)
-
-# HTML generation
-from nru_worksheet_html import (  # noqa: F401
-    generate_nru_html,
-    generate_nru_worksheet_html,
-)
-
-# PDF generation
-from nru_worksheet_pdf import generate_nru_pdf  # noqa: F401
+# Backward-compat shim -- module moved to worksheet/nru_generator.py
+import importlib as _importlib
+import sys as _sys
+_sys.modules[__name__] = _importlib.import_module("worksheet.nru_generator")