tell the stop gate that already-stored is a valid outcome

[ayushcodes10]

Found by the gate firing on itself, one hour after #33 shipped.

What happened

The Stop hook fired on the two memory files this session had just written. Its reason offered exactly two ways out:

Write what the file actually says... If a file genuinely holds nothing durable, mark it done and say so.

Neither was true. The facts were already in the graph — write_episode ran earlier in the same session, before the files existed, which is exactly what the MCP tool description asks for ("call write_episode IN THE SAME TURN whenever...").

An agent following that text literally writes the facts a second time.

Why it matters more than it looks

This is not a corner case, it is the documented happy path. write_episode in the turn the thing happens, then Claude Code writes its own memory file — so every well-behaved session ends with a queued file whose content is already stored. The gate would fire on correct behaviour, every time, and ask for duplicates.

That is precisely the failure mode the three bounds in #33 exist to avoid. A gate people switch off protects nothing.

The change

The reason now names three outcomes, all ending in marking the file done:

1. write what the file says
2. already called write_episode for it — check nothing is missing, mark it done, do not write it twice
3. genuinely holds nothing durable — mark it done and say so

Testing

13 pass, including a new one pinning outcome 2 in the reason text.