Relay the gateway's wire warning on a PreToolUse allow (0.15.0)

[davidcrowe]

0.15.0 — relay the gateway's wire warning on a PreToolUse allow. Client half of gatewaystack-connect#429 (server half: davidcrowe/gatewaystack-connect#991).

What was wrong

The gateway can put a human-facing line on an allow: the billing grace nag ([ACP billing] …, per call by design) and, with #991, a fail-open ([ACP fail-open] policy could not be read; this call ran fail-open (not policy-checked)). This hook read notice (the tier-divergence flag, once per session) and never warning. Checked on the installed 0.11.0 and on main at 0.14.0: billing has been warning into the void since enforcement landed, and a server-side fail-open was silent at the terminal.

What this does

• data.warning on an allow is captured and emitted as the systemMessage, every time it arrives (the server owns the frequency).
• A hook run still writes exactly one stdout object: the tier notice and the warning share one systemMessage via allowSystemMessage(), on both allow exits (plain and scoped-token injection).
• Deny and ask paths are untouched; a stray warning on a deny never rides on it.
• Version 0.15.0 in plugin.json, marketplace.json, PLUGIN_VERSION (attestation is per version, so the new hash baselines cleanly).

Tests

test/wire-warning.test.mjs (same shape as shadow-notice.test.mjs, real hook against a stub gateway): warning verbatim on allow with no hookSpecificOutput; notice + warning joined into one message; silent with no warning; whitespace ignored; deny unchanged with the warning dropped. Full node --test green.

Rollout

Internal first per the dogfood gate. Nothing server-side depends on this; the server already sends the field.