Auto mode skips its server check on very long conversations

Auto mode lets Claude act without asking you each time, while a check decides which actions are allowed. Several parts of that check changed:

• Too much context: when the conversation is too large, no server check runs.
• Shell commands: the early check on a shell command can now retry.
• Sub-agents from code: when a script Claude runs tries to start a sub-agent, a separate helper agent, the refusal now says auto mode's check of Claude's code doesn't cover this sub-agent.