API: endpoint /schema (#78)

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

tests/api/test_endpoints_schema.py

@@ -0,0 +1,19 @@
+def test_schema_without_token_returns_401(api_client):
+    client, _ = api_client
+    resp = client.get("/api/v1/schema")
+    assert resp.status_code == 401
+
+
+def test_schema_returns_columns(api_client, valid_token_header):
+    client, _ = api_client
+    resp = client.get("/api/v1/schema", headers=valid_token_header)
+    assert resp.status_code == 200
+    data = resp.get_json()
+    assert "columns" in data
+    assert isinstance(data["columns"], list)
+    assert len(data["columns"]) > 0
+    first = data["columns"][0]
+    assert set(first.keys()) >= {"name", "type"}
+    # uid doit être présent dans le schéma DECP de test
+    names = [c["name"] for c in data["columns"]]
+    assert "uid" in names