Minor updates to Codex Rescue agent and skill text for better Sonnet subagent adherence

[studioetc]

Since updating to Sonnet 5, the agent has taken its job as a wrapper that only passes messages unchanged as a suggestion. Multiple times I have had it summarize / reword Codex output.

This PR does the following:

1. Strengthens the language for the subagent - including phrases like verbatim and in-full for emphasis.
2. Changes the opening line of the agent, so the subagent knows that it is in fact codex-rescue. Claude Code agents don't see their own name and frontmatter. There is a skill loaded into its context that references "The rescue subagent is a forwarder" - but the agent never knows IT is the rescue subagent.

I have tried to stay light touch so I don't disrupt the behaviour too much, just return it to what was intended.