[split-required] Split final 43 files (500-668 LOC) to complete refactoring

klausur-service (11 files):
- cv_gutter_repair, ocr_pipeline_regression, upload_api
- ocr_pipeline_sessions, smart_spell, nru_worksheet_generator
- ocr_pipeline_overlays, mail/aggregator, zeugnis_api
- cv_syllable_detect, self_rag

backend-lehrer (17 files):
- classroom_engine/suggestions, generators/quiz_generator
- worksheets_api, llm_gateway/comparison, state_engine_api
- classroom/models (→ 4 submodules), services/file_processor
- alerts_agent/api/wizard+digests+routes, content_generators/pdf
- classroom/routes/sessions, llm_gateway/inference
- classroom_engine/analytics, auth/keycloak_auth
- alerts_agent/processing/rule_engine, ai_processor/print_versions

agent-core (5 files):
- brain/memory_store, brain/knowledge_graph, brain/context_manager
- orchestrator/supervisor, sessions/session_manager

admin-lehrer (5 components):
- GridOverlay, StepGridReview, DevOpsPipelineSidebar
- DataFlowDiagram, sbom/wizard/page

website (2 files):
- DependencyMap, lehrer/abitur-archiv

Other: nibis_ingestion, grid_detection_service, export-doclayout-onnx

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

agent-core/brain/__init__.py

@@ -7,15 +7,31 @@ Provides:
 - KnowledgeGraph: Entity relationships and semantic connections
 """
 
-from agent_core.brain.memory_store import MemoryStore, Memory
-from agent_core.brain.context_manager import ConversationContext, ContextManager
-from agent_core.brain.knowledge_graph import KnowledgeGraph, Entity, Relationship
+from agent_core.brain.memory_models import Memory
+from agent_core.brain.memory_store import MemoryStore
+from agent_core.brain.context_models import (
+    MessageRole,
+    Message,
+    ConversationContext,
+)
+from agent_core.brain.context_manager import ContextManager
+from agent_core.brain.knowledge_models import (
+    EntityType,
+    RelationshipType,
+    Entity,
+    Relationship,
+)
+from agent_core.brain.knowledge_graph import KnowledgeGraph
 
 __all__ = [
     "MemoryStore",
     "Memory",
+    "MessageRole",
+    "Message",
     "ConversationContext",
     "ContextManager",
+    "EntityType",
+    "RelationshipType",
     "KnowledgeGraph",
     "Entity",
     "Relationship",