Per-turn effort cap for relayed messages, plus send-now ordering fixes

What

Effort is how much thinking Claude puts into a reply. A single message can now carry a limit on that effort, and several smaller changes affect the order in which messages are sent:

• turnEffortCap: user messages can now carry this value, which caps the effort level for that one turn.
• Relay handling: the relay is the part that passes turns between Claude Code and a remote connection. It now accepts turnEffortCap and passes it on only if it matches a known effort level. Any other value is ignored and a note is logged.
• Other new markers on user messages: each now carries a uuid (a unique ID) and the flags ultrathinkTyped and declaresNoSender.
• Print loop: this is the loop used when Claude Code handles input without its interactive screen. It now waits until its queue of pending messages is idle before closing input.
• Slash commands: submitting a slash command (a command typed starting with /) now carries a sentNow flag.
• Send-now snapshot: Claude Code now takes this snapshot only when a line is actually waiting to be sent.

Why

Remote or relay-driven sessions can now ask for a lower effort level on a single turn without changing the setting for the whole session. An unrecognised value is dropped, so the turn runs normally. The ordering changes mean input is no longer closed while messages are still queued.