Phase 3 : hardening qualite de code - typage strict, securite, dead code, a11y

Config strictement stricte partout (ruff, mypy --strict, bandit, vulture,
import-linter, eslint, stylelint), aucune regle desactivee "pour ne pas
casser le build" - l'existant a ete corrige pour la satisfaire plutot que
l'inverse. Hooks pre-commit locaux (language: system) bloquants.

- Typage mypy --strict propage a tout le moteur (db, screens, auth, core,
  ai, routes, puis publish/scripts/tests/app.py/build_css.py).
- Securite : fuite de handle fichier Windows corrigee dans l'export SCORM
  (routes/publish/export_scorm.py), CSRF/RNG non-crypto/xAPI documentes
  (# nosec, # NOSONAR justifies), nouveau db.json_for_script() (echappe
  "</script>" dans le JSON embarque en <script>, 25 sites).
- Architecture : imports circulaires/F811 nettoyes, contrats
  import-linter respectes, code mort retire (vulture).
- Accessibilite : 69 champs de formulaire sans label correctement
  associe corriges (for/id ou aria-label) sur 11 templates.
- ESLint/Stylelint : lot mecanique JS/CSS, regles ajustees puis
  appliquees (aucune desactivee sans verification individuelle).
- Tests : isolation du compte admin partage (nettoyage ponctuel +
  fixture de teardown automatique en filet de securite), suite complete
  verte (591 tests Python, 241 tests JS).
- SonarQube Community Build self-heberge (Docker + PostgreSQL) : rapport
  complet analyse point par point, faux positifs documentes.
- .gitattributes ajoute (LF force) : core.autocrlf=true sur cette machine
  faisait echouer ESLint (linebreak-style) via un bug connu de git
  (checkout "en place" qui ignore l'eol force sur un fichier deja
  present sur disque - contourne en supprimant puis recreant chaque
  fichier suivi).

djLint (H021, styles inline) volontairement saute pour ce commit -
backlog assume, deja documente, traite dans un lot separe.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

tests/test_ia_chat.py

@@ -4,17 +4,25 @@ ANTHROPIC_API_KEY est toujours absente en test (voir tests/conftest.py) :
 ces tests exercent donc le chemin de DÉGRADATION GRACIEUSE (message
 d'erreur clair, jamais une 500) pour l'envoi de message — pas un appel
 réel, quel que soit le .env local du poste."""
+
+from collections.abc import Callable
+from typing import Any
+
+from flask.testing import FlaskClient
+
 import screens
 
 
-def _create_jeu2d_game(client, tmp_game_slug_cleanup, name="pytest_ia_chat"):
+def _create_jeu2d_game(
+    client: FlaskClient, tmp_game_slug_cleanup: Callable[[str], str], name: str = "pytest_ia_chat"
+) -> Any:
     resp = client.post("/games/new", data={"name": name}, follow_redirects=False)
     slug = tmp_game_slug_cleanup(resp.headers["Location"].rstrip("/").split("/")[-1])
     screen_id = screens.create_screen(slug, "Scène 1", kind="jeu_2d")
     return slug, screen_id
 
 
-def test_create_and_list_conversations(client, tmp_game_slug_cleanup):
+def test_create_and_list_conversations(client: FlaskClient, tmp_game_slug_cleanup: Callable[[str], str]) -> None:
     slug, screen_id = _create_jeu2d_game(client, tmp_game_slug_cleanup)
     resp = client.post(f"/game/{slug}/screens/{screen_id}/ia-conversations")
     assert resp.status_code == 200
@@ -27,7 +35,9 @@ def test_create_and_list_conversations(client, tmp_game_slug_cleanup):
     assert conversation["id"] in ids
 
 
-def test_conversations_are_isolated_per_screen(client, tmp_game_slug_cleanup):
+def test_conversations_are_isolated_per_screen(
+    client: FlaskClient, tmp_game_slug_cleanup: Callable[[str], str]
+) -> None:
     slug, screen_id_1 = _create_jeu2d_game(client, tmp_game_slug_cleanup)
     screen_id_2 = screens.create_screen(slug, "Scène 2", kind="jeu_2d")
     client.post(f"/game/{slug}/screens/{screen_id_1}/ia-conversations")
@@ -36,7 +46,9 @@ def test_conversations_are_isolated_per_screen(client, tmp_game_slug_cleanup):
     assert resp.get_json() == []
 
 
-def test_delete_conversation_removes_it_from_the_list(client, tmp_game_slug_cleanup):
+def test_delete_conversation_removes_it_from_the_list(
+    client: FlaskClient, tmp_game_slug_cleanup: Callable[[str], str]
+) -> None:
     slug, screen_id = _create_jeu2d_game(client, tmp_game_slug_cleanup)
     conversation = client.post(f"/game/{slug}/screens/{screen_id}/ia-conversations").get_json()
 
@@ -47,12 +59,14 @@ def test_delete_conversation_removes_it_from_the_list(client, tmp_game_slug_clea
     assert all(c["id"] != conversation["id"] for c in remaining)
 
 
-def test_delete_unknown_conversation_404s(client, game):
+def test_delete_unknown_conversation_404s(client: FlaskClient, game: str) -> None:
     resp = client.delete(f"/game/{game}/ia-conversations/999999")
     assert resp.status_code == 404
 
 
-def test_send_message_persists_it_and_a_graceful_error_reply(client, tmp_game_slug_cleanup):
+def test_send_message_persists_it_and_a_graceful_error_reply(
+    client: FlaskClient, tmp_game_slug_cleanup: Callable[[str], str]
+) -> None:
     slug, screen_id = _create_jeu2d_game(client, tmp_game_slug_cleanup)
     conversation = client.post(f"/game/{slug}/screens/{screen_id}/ia-conversations").get_json()
 
@@ -67,19 +81,23 @@ def test_send_message_persists_it_and_a_graceful_error_reply(client, tmp_game_sl
     assert "Configuration IA incomplète" in body["assistant_message"]["content"]
 
 
-def test_send_message_rejects_an_empty_message(client, tmp_game_slug_cleanup):
+def test_send_message_rejects_an_empty_message(
+    client: FlaskClient, tmp_game_slug_cleanup: Callable[[str], str]
+) -> None:
     slug, screen_id = _create_jeu2d_game(client, tmp_game_slug_cleanup)
     conversation = client.post(f"/game/{slug}/screens/{screen_id}/ia-conversations").get_json()
     resp = client.post(f"/game/{slug}/ia-conversations/{conversation['id']}/messages", json={"message": "   "})
     assert resp.status_code == 400
 
 
-def test_send_message_404s_for_an_unknown_conversation(client, game):
+def test_send_message_404s_for_an_unknown_conversation(client: FlaskClient, game: str) -> None:
     resp = client.post(f"/game/{game}/ia-conversations/999999/messages", json={"message": "salut"})
     assert resp.status_code == 404
 
 
-def test_messages_history_is_persisted_and_ordered(client, tmp_game_slug_cleanup):
+def test_messages_history_is_persisted_and_ordered(
+    client: FlaskClient, tmp_game_slug_cleanup: Callable[[str], str]
+) -> None:
     slug, screen_id = _create_jeu2d_game(client, tmp_game_slug_cleanup)
     conversation = client.post(f"/game/{slug}/screens/{screen_id}/ia-conversations").get_json()
 
@@ -93,7 +111,9 @@ def test_messages_history_is_persisted_and_ordered(client, tmp_game_slug_cleanup
     assert user_contents == ["premier", "second"]
 
 
-def test_messages_are_isolated_per_conversation(client, tmp_game_slug_cleanup):
+def test_messages_are_isolated_per_conversation(
+    client: FlaskClient, tmp_game_slug_cleanup: Callable[[str], str]
+) -> None:
     slug, screen_id = _create_jeu2d_game(client, tmp_game_slug_cleanup)
     conversation_1 = client.post(f"/game/{slug}/screens/{screen_id}/ia-conversations").get_json()
     conversation_2 = client.post(f"/game/{slug}/screens/{screen_id}/ia-conversations").get_json()
@@ -104,11 +124,15 @@ def test_messages_are_isolated_per_conversation(client, tmp_game_slug_cleanup):
     assert resp.get_json() == []
 
 
-def test_first_user_message_renames_the_conversation(client, tmp_game_slug_cleanup):
+def test_first_user_message_renames_the_conversation(
+    client: FlaskClient, tmp_game_slug_cleanup: Callable[[str], str]
+) -> None:
     slug, screen_id = _create_jeu2d_game(client, tmp_game_slug_cleanup)
     conversation = client.post(f"/game/{slug}/screens/{screen_id}/ia-conversations").get_json()
 
-    client.post(f"/game/{slug}/ia-conversations/{conversation['id']}/messages", json={"message": "Crée un fond de bureau"})
+    client.post(
+        f"/game/{slug}/ia-conversations/{conversation['id']}/messages", json={"message": "Crée un fond de bureau"}
+    )
 
     conversations = client.get(f"/game/{slug}/screens/{screen_id}/ia-conversations").get_json()
     updated = next(c for c in conversations if c["id"] == conversation["id"])