Platforms that don't return a message_id after the first send (Signal,
GitHub webhooks) were causing GatewayStreamConsumer to re-enter the
"first send" path on every tool boundary, posting one platform message
per tool call (observed as 155 PR comments on a single response).
Fix: treat _message_id == "__no_edit__" as a sentinel meaning "platform
accepted the send but cannot be edited". When a tool boundary arrives
in that state, skip the message_id/accumulated/last_sent_text reset so
all continuation text is delivered once via _send_fallback_final rather
than re-posted per segment.
Also make prompt_toolkit imports in hermes_cli/commands.py optional so
gateway and test environments that lack the package can still import
resolve_command, gateway_help_lines, and COMMAND_REGISTRY.
5dea7e1ebc