fix: Restore all files lost during destructive rebase

A previous `git pull --rebase origin main` dropped 177 local commits,
losing 3400+ files across admin-v2, backend, studio-v2, website,
klausur-service, and many other services. The partial restore attempt
(660295e2) only recovered some files.

This commit restores all missing files from pre-rebase ref 98933f5e
while preserving post-rebase additions (night-scheduler, night-mode UI,
NightModeWidget dashboard integration).

Restored features include:
- AI Module Sidebar (FAB), OCR Labeling, OCR Compare
- GPU Dashboard, RAG Pipeline, Magic Help
- Klausur-Korrektur (8 files), Abitur-Archiv (5+ files)
- Companion, Zeugnisse-Crawler, Screen Flow
- Full backend, studio-v2, website, klausur-service
- All compliance SDKs, agent-core, voice-service
- CI/CD configs, documentation, scripts

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

geo-service/models/learning_node.py

@@ -0,0 +1,120 @@
+"""
+Learning Node Models
+Pydantic models for educational content nodes
+"""
+from enum import Enum
+from typing import Optional
+from pydantic import BaseModel, Field
+
+
+class LearningTheme(str, Enum):
+    """Available learning themes for geographic education."""
+    TOPOGRAPHIE = "topographie"
+    LANDNUTZUNG = "landnutzung"
+    ORIENTIERUNG = "orientierung"
+    GEOLOGIE = "geologie"
+    HYDROLOGIE = "hydrologie"
+    VEGETATION = "vegetation"
+
+
+class NodeType(str, Enum):
+    """Type of learning node interaction."""
+    QUESTION = "question"  # Multiple choice or open question
+    OBSERVATION = "observation"  # Guided observation task
+    EXPLORATION = "exploration"  # Free exploration with hints
+
+
+class Position(BaseModel):
+    """Geographic position for a learning node."""
+    latitude: float = Field(..., ge=-90, le=90, description="Latitude in degrees")
+    longitude: float = Field(..., ge=-180, le=180, description="Longitude in degrees")
+    altitude: Optional[float] = Field(None, description="Altitude in meters")
+
+
+class LearningNode(BaseModel):
+    """
+    A learning node (station) within a geographic area.
+
+    Contains educational content tied to a specific location,
+    including questions, hints, and explanations.
+    """
+    id: str = Field(..., description="Unique node identifier")
+    aoi_id: str = Field(..., description="Parent AOI identifier")
+    title: str = Field(..., min_length=1, max_length=100, description="Node title")
+    theme: LearningTheme = Field(..., description="Learning theme")
+    position: dict = Field(..., description="Geographic position")
+    question: str = Field(..., description="Learning question or task")
+    hints: list[str] = Field(default_factory=list, description="Progressive hints")
+    answer: str = Field(..., description="Correct answer or expected observation")
+    explanation: str = Field(..., description="Didactic explanation")
+    node_type: NodeType = Field(NodeType.QUESTION, description="Interaction type")
+    points: int = Field(10, ge=1, le=100, description="Points awarded for completion")
+    approved: bool = Field(False, description="Teacher-approved for student use")
+    media: Optional[list[dict]] = Field(None, description="Associated media files")
+    tags: Optional[list[str]] = Field(None, description="Content tags")
+    difficulty: Optional[str] = Field(None, description="Difficulty level")
+    grade_level: Optional[str] = Field(None, description="Target grade level")
+
+    class Config:
+        json_schema_extra = {
+            "example": {
+                "id": "node-001",
+                "aoi_id": "550e8400-e29b-41d4-a716-446655440000",
+                "title": "Höhenbestimmung",
+                "theme": "topographie",
+                "position": {"latitude": 47.7085, "longitude": 9.1925},
+                "question": "Schätze die Höhe dieses Punktes über dem Meeresspiegel.",
+                "hints": [
+                    "Schau dir die Vegetation an.",
+                    "Vergleiche mit dem Seespiegel des Bodensees (395m).",
+                ],
+                "answer": "Ca. 430 Meter über NN",
+                "explanation": "Die Höhe lässt sich aus der Vegetation und der relativen Position zum Bodensee abschätzen.",
+                "node_type": "question",
+                "points": 10,
+                "approved": True,
+            }
+        }
+
+
+class LearningNodeRequest(BaseModel):
+    """Request model for creating a learning node manually."""
+    title: str = Field(..., min_length=1, max_length=100)
+    theme: LearningTheme
+    position: Position
+    question: str
+    hints: list[str] = Field(default_factory=list)
+    answer: str
+    explanation: str
+    node_type: NodeType = NodeType.QUESTION
+    points: int = Field(10, ge=1, le=100)
+    tags: Optional[list[str]] = None
+    difficulty: Optional[str] = Field(None, pattern="^(leicht|mittel|schwer)$")
+    grade_level: Optional[str] = None
+
+
+class LearningNodeBatch(BaseModel):
+    """Batch of learning nodes for bulk operations."""
+    nodes: list[LearningNode]
+    total_points: int = 0
+
+    def calculate_total_points(self) -> int:
+        """Calculate total points from all nodes."""
+        self.total_points = sum(node.points for node in self.nodes)
+        return self.total_points
+
+
+class LearningProgress(BaseModel):
+    """Student progress through learning nodes."""
+    student_id: str
+    aoi_id: str
+    completed_nodes: list[str] = Field(default_factory=list)
+    total_points: int = 0
+    started_at: Optional[str] = None
+    completed_at: Optional[str] = None
+
+    @property
+    def completion_percentage(self) -> float:
+        """Calculate completion percentage."""
+        # Would need total node count for accurate calculation
+        return len(self.completed_nodes) * 10  # Placeholder