Expand terminal filesystem, add mainframe hint cron, redirect PHP logs

- Game1 terminal: flesh out the virtual filesystem with a realistic
  spread of Linux directories/files (~70 dirs, ~140 files) so it no
  longer reads as an obviously small puzzle set, without touching any
  win-condition or rapport files.
- Add app:hints:check command + a php-cron container (BusyBox crond)
  that nudges players who haven't contacted every teammate 5 minutes
  into a session, via a new 'hint' Mercure message type.
- Log the cron command's output to var/log/cron/cron.log and rotate
  it (25MB / 90 days) via logrotate, run daily from the same crontab.
- Redirect PHP's error_log and Symfony's prod app/deprecation logs
  from stderr-only into var/log/php/*.log (kept alongside stderr),
  with the same rotation policy.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

assets/game1/filesystem/var/log/dmesg

@@ -0,0 +1,4 @@
+[    0.000000] Linux version 6.1.0-21-amd64 (debian-kernel@lists.debian.org)
+[    0.004211] Command line: BOOT_IMAGE=/boot/vmlinuz-6.1.0-21-amd64 root=UUID=8f14e45f
+[    0.512033] ACPI: Core revision 20221020
+[    1.221004] usb 1-1: new high-speed USB device number 2