[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>

backend-lehrer/classroom/models_session.py

@@ -0,0 +1,137 @@
+"""
+Classroom API - Session & Phase Pydantic Models.
+"""
+
+from typing import Dict, List, Optional, Any
+from pydantic import BaseModel, Field
+
+
+# === Session Models ===
+
+class CreateSessionRequest(BaseModel):
+    """Request zum Erstellen einer neuen Session."""
+    teacher_id: str = Field(..., description="ID des Lehrers")
+    class_id: str = Field(..., description="ID der Klasse")
+    subject: str = Field(..., description="Unterrichtsfach")
+    topic: Optional[str] = Field(None, description="Thema der Stunde")
+    phase_durations: Optional[Dict[str, int]] = Field(
+        None,
+        description="Optionale individuelle Phasendauern in Minuten"
+    )
+
+
+class NotesRequest(BaseModel):
+    """Request zum Aktualisieren von Notizen."""
+    notes: str = Field("", description="Stundennotizen")
+    homework: str = Field("", description="Hausaufgaben")
+
+
+class ExtendTimeRequest(BaseModel):
+    """Request zum Verlaengern der aktuellen Phase (Feature f28)."""
+    minutes: int = Field(5, ge=1, le=30, description="Zusaetzliche Minuten (1-30)")
+
+
+class PhaseInfo(BaseModel):
+    """Informationen zu einer Phase."""
+    phase: str
+    display_name: str
+    icon: str
+    duration_minutes: int
+    is_completed: bool
+    is_current: bool
+    is_future: bool
+
+
+class TimerStatus(BaseModel):
+    """Timer-Status einer Phase."""
+    remaining_seconds: int
+    remaining_formatted: str
+    total_seconds: int
+    total_formatted: str
+    elapsed_seconds: int
+    elapsed_formatted: str
+    percentage_remaining: int
+    percentage_elapsed: int
+    percentage: int = Field(description="Alias fuer percentage_remaining (Visual Timer)")
+    warning: bool
+    overtime: bool
+    overtime_seconds: int
+    overtime_formatted: Optional[str]
+    is_paused: bool = Field(False, description="Ist der Timer pausiert?")
+
+
+class SuggestionItem(BaseModel):
+    """Ein Aktivitaets-Vorschlag."""
+    id: str
+    title: str
+    description: str
+    activity_type: str
+    estimated_minutes: int
+    icon: str
+    content_url: Optional[str]
+
+
+class SessionResponse(BaseModel):
+    """Vollstaendige Session-Response."""
+    session_id: str
+    teacher_id: str
+    class_id: str
+    subject: str
+    topic: Optional[str]
+    current_phase: str
+    phase_display_name: str
+    phase_started_at: Optional[str]
+    lesson_started_at: Optional[str]
+    lesson_ended_at: Optional[str]
+    timer: TimerStatus
+    phases: List[PhaseInfo]
+    phase_history: List[Dict[str, Any]]
+    notes: str
+    homework: str
+    is_active: bool
+    is_ended: bool
+    is_paused: bool = Field(False, description="Ist die Stunde pausiert?")
+
+
+class SuggestionsResponse(BaseModel):
+    """Response fuer Vorschlaege."""
+    suggestions: List[SuggestionItem]
+    current_phase: str
+    phase_display_name: str
+    total_available: int
+
+
+class PhasesListResponse(BaseModel):
+    """Liste aller verfuegbaren Phasen."""
+    phases: List[Dict[str, Any]]
+
+
+class ActiveSessionsResponse(BaseModel):
+    """Liste aktiver Sessions."""
+    sessions: List[Dict[str, Any]]
+    count: int
+
+
+# === Session History Models ===
+
+class SessionHistoryItem(BaseModel):
+    """Einzelner Eintrag in der Session-History."""
+    session_id: str
+    teacher_id: str
+    class_id: str
+    subject: str
+    topic: Optional[str]
+    lesson_started_at: Optional[str]
+    lesson_ended_at: Optional[str]
+    total_duration_minutes: Optional[int]
+    phases_completed: int
+    notes: str
+    homework: str
+
+
+class SessionHistoryResponse(BaseModel):
+    """Response fuer Session-History."""
+    sessions: List[SessionHistoryItem]
+    total_count: int
+    limit: int
+    offset: int