Some LLM providers output literal \n characters (backslash-n) instead of actual
newlines. This causes WhatsApp to display the escape sequences as text rather
than rendering line breaks.
Add normalizeOutboundTextNewlines() to convert literal \n, \r\n, and \r escape
sequences to actual newlines before sending messages via the WhatsApp adapter.
Fixes#3082
Co-Authored-By: Claude <noreply@anthropic.com>