Copilot's fifth pass: one comment, and the completion of the previous round's
fix. Seeding the editor from `replayableParams` stopped it *offering* a key
the dispatcher would drop, but nothing stopped one being typed in — adding
`_meta` to a `tools/list` draft still let Send close the modal and discard it.
`parseParamsDraft` now takes the method and rejects any key the dispatch would
not read, so Send is disabled with the offending names rather than silently
dropping them. It asks the same `replayableParams` the seed is built from, so
the editor and the dispatcher cannot disagree about which keys survive.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UL9retfvAXRgvi6EWk4SY4
Signed-off-by: cliffhall <cliff@futurescale.com>