v5.28.0 — LTS support/v5.20 tip

LTS line support/v5.20 — tip v5.28.0

Tip of the 5.2x LTS band.

npm i node-red-contrib-modbus@5.28.0

What this LTS tip brings

• New Modbus Flex-FC node (custom FCs, request map, templates)
• Expanded client editor options/tabs; show-warnings optionals
• Delay-on-start / ready-for-input across Getter, Flex-*, Write
• Server hardening around disableMsgOutput (#333)
• Packaging fixes for @openp4nr fork and FlowForge routes

Maintenance branch: support/v5.20

CHANGELOG