Replace separate SupportMailbox with NewConversationStrategy as the
final fallback in the conversation finder chain. This prevents emails
from being silently dropped when routing rules match but no existing
conversation is found.
Previously, emails could route to ReplyMailbox (based on headers or
channel matching) but get dropped if ReferencesStrategy failed to find
a conversation. This happened when two Chatwoot accounts emailed each
other - References header contained conversation IDs from both accounts,
routing matched globally, but scoped queries found nothing.
Shivam Mishra
84993485b2