Handle WeChat location messages

[thisnick]

Problem

WeChat location messages (shared locations / real-time location sharing) are not currently handled by the agent. When a user sends a location, it's either dropped or arrives as raw XML without being parsed.

Expected behavior

• Parse WeChat location message XML (<msg><location ...>)
• Extract coordinates (latitude/longitude), label, and POI name
• Forward structured location data to the agent (e.g. as a text summary or structured metadata)
• Support both static shared locations and real-time location sharing

Notes

• Location messages use a different XML schema than regular text/image/voice messages
• May need to handle both type=48 (location) messages and location-sharing invitations