fix(data): corrige le typage de l'import historique

apps/backend/app/etl/historical_import.py

@@ -5,7 +5,7 @@ import asyncio
 import hashlib
 import json
 from pathlib import Path
-from typing import Any
+from typing import Any, cast
 
 import pandas as pd
 from sqlalchemy import text
@@ -56,7 +56,12 @@ def compute_sha256(path: Path) -> str:
 def load_metadata(path: Path) -> dict[str, Any]:
     """Charge les métadonnées fournies avec le dataset."""
     with path.open("r", encoding="utf-8") as source:
-        return json.load(source)
+        metadata = json.load(source)
+
+    if not isinstance(metadata, dict):
+        raise ValueError("Le fichier de métadonnées doit contenir un objet JSON.")
+
+    return cast(dict[str, Any], metadata)
 
 
 def classify_quality(
@@ -260,7 +265,8 @@ async def upsert_sites(
     frame: pd.DataFrame,
 ) -> None:
     """Insère ou met à jour les sites du dataset."""
-    sites = (
+    sites = cast(
+        list[dict[str, Any]],
         frame[
             [
                 "site_id",
@@ -269,7 +275,7 @@ async def upsert_sites(
             ]
         ]
         .drop_duplicates(subset=["site_id"])
-        .to_dict(orient="records")
+        .to_dict(orient="records"),
     )
 
     await connection.execute(
@@ -305,7 +311,12 @@ def build_reading_batch(
     """
     rows: list[dict[str, Any]] = []
 
-    for record in chunk.to_dict(orient="records"):
+    records = cast(
+        list[dict[str, Any]],
+        chunk.to_dict(orient="records"),
+    )
+
+    for record in records:
         quality, reasons = classify_quality(record)
 
         raw_data = {

apps/backend/pyproject.toml

@@ -27,6 +27,7 @@ dev = [
     "pytest-asyncio>=1.4.0",
     "pytest-cov>=7.1.0",
     "httpx>=0.28.1",
+    "pandas-stubs>=3.0.5.260914",
 ]
 
 [build-system]

apps/backend/uv.lock

@@ -330,6 +330,7 @@ dependencies = [
 dev = [
     { name = "httpx" },
     { name = "mypy" },
+    { name = "pandas-stubs" },
     { name = "pytest" },
     { name = "pytest-asyncio" },
     { name = "pytest-cov" },
@@ -357,6 +358,7 @@ requires-dist = [
 dev = [
     { name = "httpx", specifier = ">=0.28.1" },
     { name = "mypy", specifier = ">=2.3.1" },
+    { name = "pandas-stubs", specifier = ">=3.0.5.260914" },
     { name = "pytest", specifier = ">=9.1.1" },
     { name = "pytest-asyncio", specifier = ">=1.4.0" },
     { name = "pytest-cov", specifier = ">=7.1.0" },
@@ -669,6 +671,18 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/d2/cf/6a51b2c38980e04c279fd2fa908a1b0982064e860444acfca4ec2e2c8359/pandas-3.0.5-cp314-cp314t-win_arm64.whl", hash = "sha256:3c5015fd1730fbf883647e88068176c839c102cea883ba1769a6f4593bfc1f8c", size = 9509776, upload-time = "2026-07-22T22:19:26.694Z" },
 ]
 
+[[package]]
+name = "pandas-stubs"
+version = "3.0.5.260914"
+source = { registry = "https://pypi.org/simple" }
+dependencies = [
+    { name = "numpy" },
+]
+sdist = { url = "https://files.pythonhosted.org/packages/c1/93/8948ae6c1e1e3d6833596fd266f7be2d27c1451b8be094975ad42c5e842e/pandas_stubs-3.0.5.260914.tar.gz", hash = "sha256:3f6fc1f147f68fd89c007105e7c94a948acb4ecd7eb20dc1c02e153c4ed5c250", size = 117622, upload-time = "2026-09-14T16:42:35.065Z" }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/9a/cb/5ad79e02a556cc23fed5816de0109fa8af660c66cfa5f4af74c3e8d4cd26/pandas_stubs-3.0.5.260914-py3-none-any.whl", hash = "sha256:39a1300c5c5c55fdf609e3476805decce5d5015539a4dcb683449f8feaeee2fb", size = 177344, upload-time = "2026-09-14T16:42:33.771Z" },
+]
+
 [[package]]
 name = "pathspec"
 version = "1.1.1"