httpx emits a DeprecationWarning when verify=<str> is passed, recommending
ssl.SSLContext instead. This affected both our httpx client factories and
the caldav library passthrough.
Changed get_nextcloud_ssl_verify() to return bool | ssl.SSLContext instead
of bool | str by constructing an SSLContext when NEXTCLOUD_CA_BUNDLE is set.
All downstream consumers (httpx, caldav) natively accept ssl.SSLContext.
Also fixed app password endpoint tests that used overly broad MagicMock
(auto-generated truthy nextcloud_ca_bundle attribute).
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>