Restructure: Move final 12 root files into packages (klausur-service)

ocr/spell/  (3): smart_spell, core, text
upload/     (3): api, chunked, mobile
crawler/    (3): github, github_core, github_parsers
+ unified_grid → grid/, tesseract_extractor → ocr/engines/, htr_api → ocr/pipeline/

12 shims added. Only main.py, config.py, storage + RAG files remain at root.

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

klausur-service/backend/smart_spell.py

@@ -1,25 +1,4 @@
-"""
-SmartSpellChecker — barrel re-export.
-
-All implementation split into:
-  smart_spell_core — init, data types, language detection, word correction
-  smart_spell_text — full text correction, boundary repair, context split
-
-Lizenz: Apache 2.0 (kommerziell nutzbar)
-"""
-
-# Core: data types, lang detection (re-exported for tests)
-from smart_spell_core import (  # noqa: F401
-    _AVAILABLE,
-    _DIGIT_SUBS,
-    _SUSPICIOUS_CHARS,
-    _UMLAUT_MAP,
-    _TOKEN_RE,
-    _I_FOLLOWERS,
-    _A_FOLLOWERS,
-    CorrectionResult,
-    Lang,
-)
-
-# Text: SmartSpellChecker class (the main public API)
-from smart_spell_text import SmartSpellChecker  # noqa: F401
+# Backward-compat shim -- module moved to ocr/spell/smart_spell.py
+import importlib as _importlib
+import sys as _sys
+_sys.modules[__name__] = _importlib.import_module("ocr.spell.smart_spell")