fix: address final review findings for foundation plan

- C1: drop module-level app singleton in app/main.py so importing the
  package no longer validates Settings or creates DATA_DIR; run uvicorn
  with --factory in the Dockerfile. pytest now collects and passes with
  no ambient env vars.
- I2: add missing app/auth, app/security, app/web __init__.py so
  setuptools discovers all five packages.
- I3: resolve the Jinja2 template directory relative to __file__ instead
  of the process CWD.
- I4: add .gitignore covering .env, data/, .venv/, caches and build
  artifacts so example deployment secrets cannot be committed.
- I5: assert UserRepository.list_enabled() excludes disabled users.
- M6: encode both operands before hmac.compare_digest in validate_csrf so
  a non-ASCII token yields 403 instead of an unhandled 500.
- M9: remove unused relationship / HealthState imports.
- M11: make session cookie https_only configurable via SESSION_HTTPS_ONLY
  (default unchanged: false).
- M13: dispose SQLAlchemy engines in the db_session and client fixtures.

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

tests/web/test_users.py

@@ -225,6 +225,23 @@ def test_create_user_rejects_invalid_csrf(client: TestClient) -> None:
     assert response.status_code == 403
 
 
+def test_create_user_rejects_non_ascii_csrf_token(client: TestClient) -> None:
+    login(client)
+    response = client.post(
+        "/users",
+        data={
+            "csrf_token": "invalid-tokeü",
+            "name": "Max",
+            "mywhoosh_email": "max@example.com",
+            "mywhoosh_password": "mw-secret",
+            "garmin_email": "max-garmin@example.com",
+            "garmin_password": "garmin-secret",
+            "enabled": "on",
+        },
+    )
+    assert response.status_code == 403
+
+
 def test_dashboard_lists_created_user_without_secrets(client: TestClient) -> None:
     login(client)
     create_user_via_http(client)