fix(caldav): correct macOS client detection for schedule-outbox suppression

[clemenstyp]

Summary

SOGo suppresses the schedule-outbox resourcetype on the user's personal
calendar collection for Apple clients, since macOS/iOS clients reject a
collection that advertises itself as both a regular calendar collection and a
schedule-outbox at the same time (this is invalid per RFC 4791 / RFC 6638
and causes the collection to be ignored by the client).

The detection relied on the User-Agent header containing both macOS and
dataaccessd. Starting with macOS 26 ("OS X 26"), the Reminders app no longer
uses dataaccessd but reports a different agent string, e.g.:

macOS/26.5.1 (25F80) remindd/3976

As a result, the macOS check no longer matches, the schedule-outbox element
is added to the personal collection, and the affected list (e.g. the user's
default "Privat"/personal reminders list) no longer shows up in the macOS
Reminders app. Only lists without the schedule-outbox marker remain visible.

Root cause

The User-Agent heuristic only accounted for the legacy dataaccessd process
name and did not cover newer Apple client processes such as remindd.

Fix

Broaden the macOS client detection so that requests coming from current Apple
clients are recognized regardless of the specific process name. Instead of
matching on dataaccessd only, the check now also matches other known Apple
client agents (e.g. remindd) / relies on the macOS/ token combined with a
known Apple client component.

Steps to reproduce

1. Use a macOS 26 client and connect the Reminders app to a SOGo CalDAV account.
2. Perform a PROPFIND on /SOGo/dav/<user>/Calendar/.
3. Observe that the personal collection's <D:resourcetype> contains
   <schedule-outbox xmlns="urn:ietf:params:xml:ns:caldav"/> in addition to
   <calendar/>.
4. The personal reminders list does not appear in the Reminders app, while
   other lists (without the outbox marker) do.

Before / After

Observed User-Agent from macOS 26 Reminders:

macOS/26.5.1 (25F80) remindd/3976

• Before: not detected as macOS → schedule-outbox added → list hidden.
• After: detected as macOS → schedule-outbox omitted → list visible.

Notes

There is no existing issue for this; I was unable to open one in the Mantis
bug tracker due to lacking permissions. Happy to adjust the detection approach
(e.g. explicit process allow-list vs. broader matching) based on maintainer
preference.