Feature Request

Description

Add support for receiving and processing messages from WhatsApp Channels (Newsletters).

Current Behavior

• Newsletter messages arrive via Baileys messages.upsert with JIDs ending in @newsletter
• They are treated as DMs and blocked by dmPolicy: allowlist

Use Case

Monitoring WhatsApp news channels (e.g. Israeli emergency alert channels) and forwarding relevant content. Baileys already supports newsletters but the gateway filters them.

Proposed

Add newsletterPolicy config + separate access control path for @newsletter JIDs