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_collision_overlay_markup.py

@@ -4,25 +4,37 @@
 sa taille". Rendu SEULEMENT pour l'objet sélectionné (voir
 static/js/scenes/scene-editor.js::onCollisionBoxMouseDown/
 onCollisionBoxResizeMouseDown pour le glisser-déplacer/redimensionner)."""
+
 import re
+from collections.abc import Callable
+from typing import Any
+
+from flask.testing import FlaskClient
 
 import screens
+from tests.conftest import not_none
 
 
-def _create_jeu2d_game(client, tmp_game_slug_cleanup, name="pytest_overlay"):
+def _create_jeu2d_game(
+    client: FlaskClient, tmp_game_slug_cleanup: Callable[[str], str], name: str = "pytest_overlay"
+) -> 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 _add_decor(client, slug, screen_id):
-    resp = client.post(f"/game/{slug}/screens/{screen_id}/scene-objects/add", data={"kind": "decor"}, follow_redirects=False)
+def _add_decor(client: FlaskClient, slug: str, screen_id: int) -> Any:
+    resp = client.post(
+        f"/game/{slug}/screens/{screen_id}/scene-objects/add", data={"kind": "decor"}, follow_redirects=False
+    )
     assert resp.status_code == 302, resp.data
-    return int(re.search(r"selected=(\d+)", resp.headers["Location"]).group(1))
+    return int(not_none(re.search(r"selected=(\d+)", resp.headers["Location"])).group(1))
 
 
-def test_selected_object_renders_the_collision_overlay_with_drag_handlers(client, tmp_game_slug_cleanup):
+def test_selected_object_renders_the_collision_overlay_with_drag_handlers(
+    client: FlaskClient, tmp_game_slug_cleanup: Callable[[str], str]
+) -> None:
     slug, screen_id = _create_jeu2d_game(client, tmp_game_slug_cleanup)
     obj_id = _add_decor(client, slug, screen_id)
 
@@ -32,7 +44,9 @@ def test_selected_object_renders_the_collision_overlay_with_drag_handlers(client
     assert f"onCollisionBoxResizeMouseDown(event, {obj_id})" in html
 
 
-def test_only_the_selected_object_gets_an_overlay(client, tmp_game_slug_cleanup):
+def test_only_the_selected_object_gets_an_overlay(
+    client: FlaskClient, tmp_game_slug_cleanup: Callable[[str], str]
+) -> None:
     slug, screen_id = _create_jeu2d_game(client, tmp_game_slug_cleanup)
     obj_id = _add_decor(client, slug, screen_id)
     _add_decor(client, slug, screen_id)  # un second objet, jamais sélectionné ici
@@ -41,7 +55,9 @@ def test_only_the_selected_object_gets_an_overlay(client, tmp_game_slug_cleanup)
     assert html.count('id="collisionBoxOverlay"') == 1
 
 
-def test_overlay_reflects_a_custom_collision_box_size_and_offset(client, tmp_game_slug_cleanup):
+def test_overlay_reflects_a_custom_collision_box_size_and_offset(
+    client: FlaskClient, tmp_game_slug_cleanup: Callable[[str], str]
+) -> None:
     slug, screen_id = _create_jeu2d_game(client, tmp_game_slug_cleanup)
     obj_id = _add_decor(client, slug, screen_id)
     client.post(
@@ -54,9 +70,11 @@ def test_overlay_reflects_a_custom_collision_box_size_and_offset(client, tmp_gam
     assert "width:40.0px; height:40.0px" in html
 
 
-def test_disabled_collision_marks_the_overlay(client, tmp_game_slug_cleanup):
+def test_disabled_collision_marks_the_overlay(client: FlaskClient, tmp_game_slug_cleanup: Callable[[str], str]) -> None:
     slug, screen_id = _create_jeu2d_game(client, tmp_game_slug_cleanup)
     obj_id = _add_decor(client, slug, screen_id)
-    client.post(f"/game/{slug}/scene-objects/{obj_id}/collision", data='{"enabled": false}', content_type="application/json")
+    client.post(
+        f"/game/{slug}/scene-objects/{obj_id}/collision", data='{"enabled": false}', content_type="application/json"
+    )
     html = client.get(f"/game/{slug}/screens/{screen_id}/edit?selected={obj_id}").get_data(as_text=True)
     assert "is-disabled" in html