Add comprehensive test suite for image processing and related services

- Implement tests for database generator to ensure proper session handling.
- Create tests for EXIF extraction and conversion functions.
- Add tests for image-related endpoints, ensuring proper data retrieval and isolation between clients.
- Develop tests for OCR functionality, including language detection and text extraction.
- Introduce tests for the image processing pipeline, covering success and failure scenarios.
- Validate rate limiting functionality and ensure independent counters for different clients.
- Implement scraper tests to verify HTML content fetching and error handling.
- Add unit tests for various services, including storage and filename generation.
- Establish worker entry point for ARQ to handle background image processing tasks.

app/models/client.py

@@ -0,0 +1,70 @@
+"""
+Modèle SQLAlchemy — APIClient : clients authentifiés du hub
+"""
+import enum
+import uuid as uuid_lib
+from datetime import datetime, timezone
+from sqlalchemy import (
+    Column, String, JSON, Boolean, DateTime, Enum as SAEnum,
+    BigInteger, Integer,
+)
+from sqlalchemy.orm import relationship
+from app.database import Base
+
+
+class ClientPlan(str, enum.Enum):
+    FREE = "free"
+    STANDARD = "standard"
+    PREMIUM = "premium"
+
+
+class APIClient(Base):
+    __tablename__ = "api_clients"
+
+    # ── Identité ──────────────────────────────────────────────
+    id = Column(
+        String(36),
+        primary_key=True,
+        default=lambda: str(uuid_lib.uuid4()),
+        index=True,
+    )
+    name = Column(String(256), nullable=False)
+
+    # ── Authentification ──────────────────────────────────────
+    api_key_hash = Column(String(64), nullable=False, unique=True, index=True)
+
+    # ── Permissions ───────────────────────────────────────────
+    scopes = Column(JSON, nullable=False, default=list)
+    plan = Column(
+        SAEnum(ClientPlan),
+        default=ClientPlan.FREE,
+        nullable=False,
+    )
+    is_active = Column(Boolean, default=True, nullable=False)
+
+    # ── Quota tracking ─────────────────────────────────────────
+    storage_used_bytes = Column(BigInteger, default=0, nullable=False)
+    quota_storage_mb = Column(Integer, default=500, nullable=False)
+    quota_images = Column(Integer, default=1000, nullable=False)
+
+    # ── Timestamps ────────────────────────────────────────────
+    created_at = Column(DateTime, default=lambda: datetime.now(timezone.utc))
+    updated_at = Column(
+        DateTime,
+        default=lambda: datetime.now(timezone.utc),
+        onupdate=lambda: datetime.now(timezone.utc),
+    )
+
+    # ── Relations (ajoutée par Livrable 1.2) ──────────────────
+    images = relationship(
+        "Image",
+        back_populates="client",
+        cascade="all, delete-orphan",
+    )
+
+    def __repr__(self) -> str:
+        return f"<APIClient id={self.id} name={self.name} plan={self.plan}>"
+
+    def has_scope(self, scope: str) -> bool:
+        """Vérifie si le client possède le scope demandé."""
+        return scope in (self.scopes or [])