Cleanup: Delete ALL 242 shims, update ALL consumer imports

klausur-service: 183 shims deleted, 26 test files + 8 source files updated
backend-lehrer: 59 shims deleted, main.py + 8 source files updated

All imports now use the new package paths directly.
Zero shims remaining in the entire codebase.

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

klausur-service/backend/tests/test_advanced_rag.py

@@ -257,7 +257,7 @@ class TestPDFExtraction:
 
     def test_pdf_extraction_config(self):
         """Test PDF extraction configuration."""
-        from pdf_extraction import PDF_BACKEND, get_pdf_extraction_info
+        from korrektur.pdf_extraction import PDF_BACKEND, get_pdf_extraction_info
 
         info = get_pdf_extraction_info()
         assert "configured_backend" in info
@@ -266,7 +266,7 @@ class TestPDFExtraction:
 
     def test_detect_available_backends(self):
         """Test backend detection."""
-        from pdf_extraction import _detect_available_backends
+        from korrektur.pdf_extraction import _detect_available_backends
 
         backends = _detect_available_backends()
         assert isinstance(backends, list)
@@ -280,7 +280,7 @@ class TestPDFExtraction:
 
     def test_pdf_extraction_result_class(self):
         """Test PDFExtractionResult data class."""
-        from pdf_extraction import PDFExtractionResult
+        from korrektur.pdf_extraction import PDFExtractionResult
 
         result = PDFExtractionResult(
             text="Extracted text",
@@ -305,7 +305,7 @@ class TestPDFExtraction:
 
     def test_pdf_extraction_error(self):
         """Test PDF extraction error handling."""
-        from pdf_extraction import PDFExtractionError
+        from korrektur.pdf_extraction import PDFExtractionError
 
         with pytest.raises(PDFExtractionError):
             raise PDFExtractionError("Test error")
@@ -313,7 +313,7 @@ class TestPDFExtraction:
     @pytest.mark.xfail(reason="_extract_with_pypdf is internal function not exposed in API")
     def test_pypdf_extraction(self):
         """Test pypdf extraction with a simple PDF (BSD-3-Clause licensed)."""
-        from pdf_extraction import _extract_with_pypdf, PDFExtractionError
+        from korrektur.pdf_extraction import _extract_with_pypdf, PDFExtractionError
 
         # Create a minimal valid PDF
         # This is a very simple PDF that PyPDF2 can parse
@@ -517,7 +517,7 @@ class TestModuleAvailability:
 
     def test_pdf_extraction_import(self):
         """Test PDF Extraction module import."""
-        from pdf_extraction import (
+        from korrektur.pdf_extraction import (
             extract_text_from_pdf,
             extract_text_from_pdf_enhanced,
             get_pdf_extraction_info,
@@ -551,7 +551,7 @@ class TestFeatureVerification:
         from hyde import get_hyde_info
         from hybrid_search import get_hybrid_search_info
         from rag_evaluation import get_evaluation_info
-        from pdf_extraction import get_pdf_extraction_info
+        from korrektur.pdf_extraction import get_pdf_extraction_info
         from self_rag import get_self_rag_info
 
         infos = [
@@ -598,7 +598,7 @@ class TestRAGAdminAPI:
     @pytest.mark.asyncio
     async def test_rag_documentation_markdown_format(self):
         """Test RAG documentation endpoint returns markdown."""
-        from admin_api import get_rag_documentation
+        from admin.api import get_rag_documentation
 
         result = await get_rag_documentation(format="markdown")
 
@@ -610,7 +610,7 @@ class TestRAGAdminAPI:
     @pytest.mark.asyncio
     async def test_rag_documentation_html_format(self):
         """Test RAG documentation endpoint returns HTML with tables."""
-        from admin_api import get_rag_documentation
+        from admin.api import get_rag_documentation
 
         result = await get_rag_documentation(format="html")
 
@@ -628,7 +628,7 @@ class TestRAGAdminAPI:
     @pytest.mark.asyncio
     async def test_rag_system_info_has_feature_status(self):
         """Test RAG system-info includes feature status."""
-        from admin_api import get_rag_system_info
+        from admin.api import get_rag_system_info
 
         result = await get_rag_system_info()
 
@@ -639,7 +639,7 @@ class TestRAGAdminAPI:
     @pytest.mark.asyncio
     async def test_rag_system_info_has_privacy_notes(self):
         """Test RAG system-info includes privacy notes."""
-        from admin_api import get_rag_system_info
+        from admin.api import get_rag_system_info
 
         result = await get_rag_system_info()