Fix chat call link opening

[Texaglo]

Summary

• prevent the chat call card from following its native target="_blank" anchor
• open the existing Jitsi room URL explicitly, matching the working call flows
• preserve scheduled-call and delete guards

Testing

• exercised immediate call creation and chat-card joining with two connected accounts on testnet
• confirmed the desktop control opens the exact Jitsi room and isolated the failing native-WebView new-window path
• loaded the patched client locally with no console errors
• node --check app.js
• git diff --check

Closes #1549