feat(chatwoot-adapter): relay the operator's own outbound sends to Chatwoot (#615)

[rmyndharis]

Summary

Relays the operator's own outbound WhatsApp messages — composed on a linked phone, the WhatsApp mobile app, or the OpenWA REST API — into the mapped Chatwoot conversation as outgoing messages, so an ongoing thread stops looking one-sided (#615).

Problem

The adapter only subscribed to message:received and dropped every fromMe message. WhatsApp delivers messages composed on a linked device through a different path (message:sent), so an operator replying from their phone alongside Chatwoot produced a broken, one-sided thread — the contact's replies showed, the operator's phone messages never did.

Changes

• Relay own sends. Subscribe to message:sent and post fromMe messages as Chatwoot outgoing, into the contact's existing mapped conversation. Gated by a new relayOwnMessages setting (default on; turn it off to keep phone-composed messages out of the helpdesk).
• Relay-into-existing only. An own send to a chat that isn't mapped yet is skipped rather than opening a new conversation. This avoids splitting a contact who has migrated to @lid — whose @c.us mapping isn't always resolvable — into a duplicate; the chat still appears once the contact replies.
• Echo-suppression. An agent's own Chatwoot reply is also fromMe and returns on message:sent. The outbound path marks the WhatsApp id it sent and the own-send handler skips anything already seen, serialized on a per-chat lock.
• @lid migration. A send to a migrated contact resolves to the @lid address, so message:sent carries chatId=@lid while the mapping is keyed @c.us. The handler canonicalizes the chat id (ctx.engine.canonicalChatId) for the lock key and does a dual lookup (raw then canonical), so a resolvable migrated contact's send lands in its existing conversation.
• Media/robustness. Type-based placeholders for caption-less media sends (photo/video/audio/document) so they never post an empty bubble, and a defensive log when a send returns no message id.

Compatibility

Version 0.4.0; minOpenWAVersion 0.8.7 (uses the new canonicalChatId host capability). Existing behavior is unchanged for inbound relay, outbound agent replies, and handover.