Restore Chat Links

Enabled JAR Signing. It will now attempt to detect and reject modification.

SHA256 Fingerprint: 8F:25:9B:45:66:CD:BC:53:6A:52:5B:79:FC:AA:35:2E:73:65:65:31:A2:38:2D:EF:3F:F6:D9:25:47:2C:81:FE

_{The system property, rcl.LoadLegacyMixin, can be used re-enable the mixin based version if required.
This system property is temporary. A future release may remove mixin based version and the system property.}