fix(backend): documente le 403 CSRF de require_trusted_origin

Le contrat OpenAPI et 31-contrat-authentification.md passaient sous
silence le 403 leve par require_trusted_origin sur refresh, logout,
logout-all et password. Ajoute REPONSE_ORIGINE_REFUSEE, regenere
openapi.json et etend test_openapi.py pour verifier que ces quatre
routes le declarent.

apps/backend/app/api/openapi.py

@@ -112,3 +112,10 @@ REPONSES_ADMIN: Final[Reponses] = {
         ),
     },
 }
+
+REPONSE_ORIGINE_REFUSEE: Final[Reponses] = {
+    403: {
+        "model": ErrorResponse,
+        "description": "Origine non autorisée (protection CSRF de `require_trusted_origin`).",
+    },
+}

apps/backend/app/api/v1/endpoints/auth.py

@@ -12,6 +12,7 @@ from app.api.deps import (
     require_trusted_origin,
 )
 from app.api.openapi import (
+    REPONSE_ORIGINE_REFUSEE,
     REPONSE_VALIDATION,
     REPONSES_AUTHENTIFIEES,
     Reponses,
@@ -61,6 +62,7 @@ REPONSES_LOGIN: Reponses = {
 }
 
 REPONSES_REFRESH: Reponses = {
+    **REPONSE_ORIGINE_REFUSEE,
     401: {
         "model": ErrorResponse,
         "description": (
@@ -70,8 +72,13 @@ REPONSES_REFRESH: Reponses = {
     },
 }
 
+REPONSES_LOGOUT: Reponses = {**REPONSE_ORIGINE_REFUSEE}
+
+REPONSES_LOGOUT_ALL: Reponses = {**REPONSES_AUTHENTIFIEES, **REPONSE_ORIGINE_REFUSEE}
+
 REPONSES_MOT_DE_PASSE: Reponses = {
     **REPONSE_VALIDATION,
+    **REPONSE_ORIGINE_REFUSEE,
     401: {
         "model": ErrorResponse,
         "description": "Jeton d'accès invalide, ou mot de passe courant faux.",
@@ -186,6 +193,7 @@ async def refresh(
     status_code=status.HTTP_204_NO_CONTENT,
     summary="Ferme la session courante",
     dependencies=[Depends(require_trusted_origin), Depends(cookie_de_rafraichissement)],
+    responses=REPONSES_LOGOUT,
 )
 async def logout(
     request: Request, response: Response, settings: SettingsDep, service: AuthServiceDep
@@ -202,7 +210,7 @@ async def logout(
     status_code=status.HTTP_204_NO_CONTENT,
     summary="Ferme toutes les sessions du compte",
     dependencies=[Depends(require_trusted_origin)],
-    responses=REPONSES_AUTHENTIFIEES,
+    responses=REPONSES_LOGOUT_ALL,
 )
 async def logout_all(
     principal: CurrentPrincipalDep,

apps/backend/openapi.json

@@ -186,6 +186,16 @@
               }
             }
           },
+          "403": {
+            "description": "Origine non autorisée (protection CSRF de `require_trusted_origin`).",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "$ref": "#/components/schemas/ErrorResponse"
+                }
+              }
+            }
+          },
           "401": {
             "description": "Cookie absent, session expirée, révoquée, ou jeton déjà tourné. Dans ce dernier cas toute la famille de sessions est révoquée et le cookie est effacé avec la réponse.",
             "content": {
@@ -224,6 +234,16 @@
                 }
               }
             }
+          },
+          "403": {
+            "description": "Origine non autorisée (protection CSRF de `require_trusted_origin`).",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "$ref": "#/components/schemas/ErrorResponse"
+                }
+              }
+            }
           }
         },
         "security": [
@@ -263,6 +283,16 @@
                 }
               }
             }
+          },
+          "403": {
+            "description": "Origine non autorisée (protection CSRF de `require_trusted_origin`).",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "$ref": "#/components/schemas/ErrorResponse"
+                }
+              }
+            }
           }
         },
         "security": [
@@ -366,6 +396,16 @@
               }
             }
           },
+          "403": {
+            "description": "Origine non autorisée (protection CSRF de `require_trusted_origin`).",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "$ref": "#/components/schemas/ErrorResponse"
+                }
+              }
+            }
+          },
           "401": {
             "description": "Jeton d'accès invalide, ou mot de passe courant faux.",
             "content": {

apps/backend/tests/api/test_openapi.py

@@ -15,6 +15,13 @@ METHODES = {"get", "post", "patch", "put", "delete"}
 # documenté y serait faux.
 SANS_REFUS = {("POST", "/api/v1/auth/logout")}
 
+ORIGINE_VERIFIEE = {
+    ("POST", "/api/v1/auth/refresh"),
+    ("POST", "/api/v1/auth/logout"),
+    ("POST", "/api/v1/auth/logout-all"),
+    ("POST", "/api/v1/auth/password"),
+}
+
 
 @pytest.fixture(scope="module")
 def schema() -> dict[str, Any]:
@@ -58,6 +65,16 @@ def test_every_administration_route_documents_the_role_refusal(schema: dict[str,
     assert sans_403 == []
 
 
+def test_every_origin_checked_route_documents_the_csrf_refusal(schema: dict[str, Any]) -> None:
+    sans_403 = [
+        (methode, chemin)
+        for methode, chemin, operation in operations(schema)
+        if (methode, chemin) in ORIGINE_VERIFIEE and "403" not in operation["responses"]
+    ]
+
+    assert sans_403 == []
+
+
 def test_the_validation_model_matches_what_the_handler_returns(schema: dict[str, Any]) -> None:
     modeles = {
         operation["responses"]["422"]["content"]["application/json"]["schema"]["$ref"]