When cc-connect send --image or --file is called without an explicit
--session flag and there are multiple active sessions, the code would
arbitrarily pick the first session from a map (non-deterministic order).
This could cause attachments to be sent to the wrong chat.
Now returns an error when multiple sessions exist and no session key is
specified for attachment sends. Also adds debug logging to Telegram SendImage
to aid future diagnosis.
Fixes#242
Co-authored-by: Dev Claude <dev@cc-connect.ai>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>