Resize images to max 1024px before AI analysis to prevent timeouts

Large images (10MB+ PNG) create huge base64 payloads that cause
OpenRouter/Gemini API timeouts. Now resized to 1024px JPEG quality 85
before sending, reducing payload from ~15MB to ~100KB.

app/services/ai_vision.py

@@ -40,15 +40,40 @@ def _get_client() -> genai.Client:
 
 
 async def _read_image(file_path: str) -> tuple[bytes, str]:
+    """Lit l'image via le StorageBackend et la redimensionne pour l'AI (max 1024px)."""
     path = Path(file_path)
     suffix = path.suffix.lower()
+    backend = get_storage_backend()
+    data = await backend.get_bytes(file_path)
+
+    # Redimensionner pour éviter les timeouts AI sur les grandes images
+    try:
+        from PIL import Image as PILImage
+        import io as pil_io
+        original_size = len(data)
+        img = PILImage.open(pil_io.BytesIO(data))
+        max_dim = 1024
+        if img.width > max_dim or img.height > max_dim:
+            img.thumbnail((max_dim, max_dim), PILImage.Resampling.LANCZOS)
+            buf = pil_io.BytesIO()
+            if img.mode in ("RGBA", "P"):
+                img = img.convert("RGB")
+            img.save(buf, format="JPEG", quality=85)
+            data = buf.getvalue()
+            logger.info("ai.image_resized", extra={
+                "file": path.name,
+                "original_bytes": original_size,
+                "resized_bytes": len(data),
+            })
+            return data, "image/jpeg"
+    except Exception:
+        pass  # Si Pillow échoue, on utilise l'image originale
+
     mime_map = {
         ".jpg": "image/jpeg", ".jpeg": "image/jpeg",
         ".png": "image/png", ".gif": "image/gif", ".webp": "image/webp",
     }
     media_type = mime_map.get(suffix, "image/jpeg")
-    backend = get_storage_backend()
-    data = await backend.get_bytes(file_path)
     return data, media_type