My previous fix made submit no longer block on isStarting, with the
goal of keeping local quick-chat sessions from silently dropping
messages. The trace from CI showed it traded one failure for another:
the editor became contenteditable while the session was still
STARTING, the e2e suite pressed Cmd+Enter immediately, and the
backend rejected with "Failed to send message to agent" because the
agent process wasn't ready yet.
Restore the original semantics — STARTING blocks both editor and
submit — but keep `isPreparingEnvironment` as the narrower trigger for
the "agent still being set up" tooltip. Net behaviour:
- STARTING transition: editor disabled, no tooltip (signal is the
disabled state itself)
- container/sandbox prepare: editor disabled + tooltip explaining why
- quick-chat sessions: editor stays disabled until RUNNING, no race
José Almeida
9389ac9c79