v5.16.0 — LTS support/v5.10 tip

LTS line support/v5.10 — tip v5.16.0

Tip of the 5.1x LTS band.

npm i node-red-contrib-modbus@5.16.0

What this LTS tip brings (5.10 → 5.16)

• Stronger FSM client: register/deregister, reconnect, less double-state traffic
• Serial queue sequencing fixes (#202)
• Keep message properties; UnitId 0 allowed for TCP
• Broadcast UnitId extraction (#195)
• Empty msg on error paths; topic preserved on reader (#200)

Maintenance branch: support/v5.10

CHANGELOG