[Bug]: gaia email --trace is a no-op on the daemon-relay query path #3345

Quick check:

• I've searched existing issues and didn't find a duplicate.
• This issue relates to Gaia Agent UI (gaia chat --ui).
• This issue relates to a CLI command (gaia ...) or the SDK.

What happened?

gaia email --trace is advertised in --help (it's defined on the shared parent_parser and inherited by the email subcommand — src/gaia/cli.py:1224-1228, attached via parents=[parent_parser] at src/gaia/cli.py:1431), but it does nothing on the path a single query actually takes.

gaia email -q '...' no longer runs the agent in-process — it goes through handle_email_command (src/gaia/cli.py:4542), which calls gaia.daemon.agent_query.run_query(...) (src/gaia/cli.py:4616-4627). That function's signature has no trace parameter at all, and the JSON payload it builds for POST /v1/<agent>/query never includes a trace key:

# src/gaia/daemon/agent_query.py:254-300
def run_query(
 agent_id: str,
 query: str,
 *,
 context=None,
 model=None,
 max_steps=None,
 session_id=None,
 renderer=None,
 verbose: bool = False,
) -> QueryOutcome:
 ...
 payload: Dict[str, Any] = {
 "query": query,
 "run_id": run_id,
 "context": context or [],
 }
 if model:
 payload["model"] = model
 if max_steps is not None:
 payload["max_steps"] = max_steps
 if session_id:
 payload["session_id"] = session_id

args.trace is parsed (it's on parent_parser) but is simply never read anywhere on this call path, so running gaia email --trace -q '...' produces no trace file and no error — it silently behaves exactly like omitting the flag.

Steps to reproduce:

1. Run gaia email --trace -q 'summarize my unread emails'.
2. Observe the query completes normally.
3. No trace JSON file is written anywhere, and nothing in stdout/stderr mentions tracing.

Two things make this harder to work around than it should be:

• The sidecar's own log (hub/agents/email/python/gaia_agent_email/server.py:43-47) only logs at INFO (tool_call/tool_result lines), and the level is hard-coded: logging.basicConfig(level=logging.INFO, ...) with no environment variable read anywhere in that file to raise verbosity.
• GET /v1/email/agent/session/{id}/history (hub/agents/email/python/gaia_agent_email/agent_routes.py:497-506) only returns user/assistant text pairs (HistoryTurn(user=u, assistant=a)), not a system prompt or per-call detail.

So there is currently no way to get GAIA's actual prompt/execution trace out of the email agent's normal query path, even though --trace looks like it should provide exactly that.

What did you expect to happen?

Either gaia email --trace writes a trace file (as advertised), or --help should not offer --trace for a subcommand where it's a no-op.

Acceptance criteria

• gaia email --trace -q '...' writes a trace artifact, OR --trace is removed/disabled (with a clear message) for the email daemon-relay path.
• If kept, document where the trace file lands.

Environment

Found while reading the CLI source (src/gaia/cli.py, src/gaia/daemon/agent_query.py) and the email sidecar (hub/agents/email/python/gaia_agent_email/) on main, while trying to capture a full execution trace for an unrelated evaluation of the email agent.