require_auth now uses HTTPBearer(auto_error=False) and raises 401 explicitly
when the Authorization header is missing or non-Bearer, matching
require_auth_401. Unauthenticated requests are 401 for every user endpoint;
authenticated-but-forbidden (cross-entity / role) stays 403.
- app/auth_middleware.py: single optional bearer, 401 on missing token
(require_auth_401 kept as a compatibility alias)
- tests: update 4 pre-existing cases that asserted 403 without a token
(test_auth, test_reports, test_kpi_causality, test_expenses,
test_api_auth_surface_20260914) - intentional behavior change
- add tests/test_auth_401_unification_20260915.py: sample + full sweep
(all AUTHED GET routes -> 401), invalid token -> 401, cross-entity and
role-denied still 403, bot channel (X-BOT-KEY) and public paths unchanged
Hermes CI Fix