Fix segfault in play media with record-egress enabled

[fergusean]

Summary

Fix a segmentation fault that occurred when issuing a "play media" command while call recording with --record-egress was active.

Root Cause

When the media player constructed a synthetic struct media_packet for the egress-recording path in media_player.c, it left the media field uninitialized (NULL). The dump_packet_pcap() function in recording.c then unconditionally dereferenced mp->media->monologue, causing a segfault.

Changes Made

• daemon/media_player.c: Initialize the media field in the synthetic struct media_packet to sink->media when constructing packets for the media player send timer. This ensures the media context is available for the egress recording path.

• daemon/recording.c: Add a defensive NULL check in dump_packet_pcap() to safely handle cases where mp->media or mp->media->monologue might be NULL, preventing crashes from incomplete packet structures.

• t/auto-daemon-tests-record-egress-play-media.pl: Add comprehensive regression test covering:

  • Play media with active call recording
  • Daemon stability after play media completes
  • RTP forwarding resumption after media playback
  • Play media in both directions (from-tag and to-tag)
  • Stop media during egress recording
  • Play media across multiple independent calls

Testing

The new test verifies the fix works correctly and prevents regression of this crash scenario when using --record-egress with the play media feature.