Add ProcessScanner::scan(ScanOptions) for combined env/cmdline/exe matching, extend Match with match-source flags, and make pollUntilFound() cancellation-aware. Update monitored launch matchers to use the new API.
Tighten transient unit lifecycle handling in GameCenter.
- Drop stale unit watcher mappings on PropertiesChanged for removed sessions.
- When stopping a monitored launch due to timeout or attach failure, fall back
to terminating scope PIDs if StopUnit fails unexpectedly.
This reduces leaked scopes and improves robustness in failure paths.
Improve GameCenter daemon handling of systemd transient scopes.
- Watch monitored-launch scopes early and avoid dropping Launching sessions
when the unit disappears before PIDs are attached.
- Stop leaked scopes on AttachProcessesToUnit failures.
- Make Stop() resilient for recovered sessions by falling back to TERM/KILL
on scope PIDs when StopUnit fails unexpectedly.
- Only recover scopes that match the expected A-La-Karte description.
Build and install the Game Center daemon as a DBus-activated\nuser service. This introduces the new src/gamecenter target and\nwires it into the main build.
