Adds an e2e test that sends a NIP-59 gift-wrap (kind 1059) to the agent —
exactly what the desktop publishes for an encrypted channel — and asserts the
agent decrypts it, extracts the channel from the inner rumor's h tag, passes the
gate, and replies. Proves the private-channel path end-to-end against live
relays; the earlier 'goose didn't reply in private' was the agent being offline,
not a code bug.
8846ef3c12