APIKeyManager.load() decrypts every stored key with a dict comprehension
and no error handling. If the .key file no longer matches the ciphertext in
api_keys.json — key rotated, a partial/!mismatched data restore, or a
corrupted .key — Fernet.decrypt raises cryptography.fernet.InvalidToken.
app_initializer.py calls api_key_manager.load() during startup, so a single
undecryptable entry takes down the whole app at boot, and the user can't
reach the UI to fix it.
Decrypt each key in a loop and, on InvalidToken/ValueError, log a warning
and skip that one entry while still returning every key that decrypts
cleanly. One bad/stale key no longer blocks startup.
tests/test_api_key_manager_resilience.py saves a valid key, then injects an
entry encrypted under a different Fernet key (InvalidToken) and a malformed
token (ValueError), and asserts load() returns the good key and skips the
bad ones without raising. Fails before this change.
