v1.3.1-alpha

Fixes repeated ?Player has joined? notices in LAN/Direct IP lobby chat. Periodic
JOIN refresh packets still update the guest's seat, BIOS, memory-card offer,
and endpoint; chat announces a new arrival once and allows a new notice after
leaving and rejoining. Both modern and legacy LAN clients are covered.

Includes all v1.3.0-alpha features and the current master baseline with
Seamless Loading. The X + Zero co-op mod remains Experimental 0.0.1.

The owner confirmed basic two-player netplay gameplay in v1.3.0-alpha.
Separate-machine Internet, rematch, and full-campaign reliability remain
outside the completed automated checks. v1.2.0 remains the stable release.

See the v1.3.0-alpha release for co-op setup and limitations.