Add admin panel, WebSocket support, and API versioning

Introduce an admin portal (React + Nginx), WebSocket routing, and
API versioning middleware with `/api/v1/` prefix deprecation.
Add master API key authentication, new Prometheus metrics for AI
token consumption and active WebSockets, and extend S3 config
with a public endpoint URL. Update test paths and fixtures to
align with the new routing structure.

sdk/imago_client/models.py

@@ -0,0 +1,84 @@
+"""
+Data models for the Imago Client SDK.
+"""
+from dataclasses import dataclass, field
+from typing import Any, Dict, List, Optional
+from datetime import datetime
+
+@dataclass
+class ExifCamera:
+    make: Optional[str] = None
+    model: Optional[str] = None
+    lens: Optional[str] = None
+    iso: Optional[int] = None
+    aperture: Optional[str] = None
+    shutter_speed: Optional[str] = None
+    focal_length: Optional[str] = None
+    flash: Optional[int] = None
+    orientation: Optional[int] = None
+    software: Optional[str] = None
+    taken_at: Optional[datetime] = None
+
+@dataclass
+class ExifGPS:
+    latitude: Optional[float] = None
+    longitude: Optional[float] = None
+    altitude: Optional[float] = None
+    has_gps: bool = False
+    maps_url: Optional[str] = None
+
+@dataclass
+class ExifData:
+    camera: Optional[ExifCamera] = None
+    gps: Optional[ExifGPS] = None
+    raw: Optional[Dict[str, Any]] = None
+
+@dataclass
+class OcrData:
+    has_text: bool = False
+    text: Optional[str] = None
+    language: Optional[str] = None
+    confidence: Optional[float] = None
+
+@dataclass
+class AiData:
+    description: Optional[str] = None
+    tags: List[str] = field(default_factory=list)
+    confidence: Optional[float] = None
+    model_used: Optional[str] = None
+    processed_at: Optional[datetime] = None
+    prompt_tokens: Optional[int] = None
+    output_tokens: Optional[int] = None
+
+@dataclass
+class ProcessingInfo:
+    status: str
+    error: Optional[str] = None
+    started_at: Optional[datetime] = None
+    done_at: Optional[datetime] = None
+
+@dataclass
+class HubImage:
+    id: int
+    uuid: str
+    original_name: str
+    mime_type: Optional[str] = None
+    file_size: Optional[int] = None
+    width: Optional[int] = None
+    height: Optional[int] = None
+    uploaded_at: Optional[datetime] = None
+    processing_status: str = "pending"
+    client_id: Optional[str] = None
+    client_name: Optional[str] = None
+    thumbnail_path: Optional[str] = None
+    
+    # Extended data
+    exif: Optional[ExifData] = None
+    ocr: Optional[OcrData] = None
+    ai: Optional[AiData] = None
+    processing: Optional[ProcessingInfo] = None
+
+    @classmethod
+    def from_dict(cls, data: Dict[str, Any]) -> "HubImage":
+        # Simplified factory method from a JSON API response
+        return cls(**{k: v for k, v in data.items() if k in cls.__dataclass_fields__ and k not in ("exif", "ocr", "ai", "processing")})