The email-account endpoints coerced user-supplied ports with a bare int(data.get("imap_port") or 993), so a non-numeric port (e.g. "imap") raised ValueError and surfaced as an HTTP 500 in the create, update, and test-config endpoints.
Add a _coerce_port(value, default) -> (port, error) helper and use it in all three endpoints, returning the endpoints standard {"ok": False, "error": ...} response (matching the existing "name required" validation) instead of crashing. A blank or missing port still falls back to the default (993/465).
_patch_prefs installs a fake routes.prefs_routes with a bare
sys.modules[...] = assignment that is never undone. The stub is an empty
ModuleType without _save_for_user, so a later test whose code path runs
`from routes.prefs_routes import _save_for_user` (e.g. test_backup_import_skills)
fails with ImportError under an unfavorable test order.
Install the stub with monkeypatch.setitem instead (the helper already takes
monkeypatch and uses it for DATA_DIR) so it is reverted at teardown.
Repro: pytest tests/test_skill_index_prompt_injection.py tests/test_backup_import_skills.py
(1 failed before, 5 passed after).
Victor