Add smartphone forwarding controls

[memphi2]

Summary

• add OpenWebNet calls for Classe 300X smartphone call forwarding status, enable, and block
• expose a dedicated /smartphone-forwarding HTTP endpoint
• add an opt-in MQTT command listener for smartphone forwarding control and state publishing
• list smartphone call forwarding in the API support overview

Why

The existing /aswm endpoint controls answering-machine/voicemail state. Smartphone call forwarding uses OpenWebNet dimension 37 instead:

• status: *#8**37##
• enable all: *#8**#37*0##
• block all: *#8**#37*2##

Validation

• node -c config.js lib/apis/smartphone-forwarding.js lib/mqtt.js lib/openwebnet.js
• git diff --check upstream/main...HEAD
• package and lockfile versions verified unchanged at 2024.9.1
• production and development bundles built with the local Webpack CLI
• privacy scan of upstream/main...HEAD for device IPs, credentials, tokens, and private SSH/user values

Note: this PR intentionally excludes the fork-only 2026.5.1 release bump.