test(trace): cover gen_ai.output.messages on turn and teammate spans

[rgao-coreweave]

Adds two missing assertions on gen_ai.output.messages. Tests only, no src/ change.

The gap

Neither the turn span nor the teammate turn span had this attribute asserted anywhere. Found by mutation: replacing the written value with undefined left all 203 tests green in both cases.

# turn span (src/session.ts recordTurnOutput)
outputMessages -> undefined   =>  203 pass, 0 fail

# teammate turn span (src/teamCoordinator.ts emitTeammate)
outputMessages -> undefined   =>  203 pass, 0 fail

The many existing ATTR.OUTPUT_MESSAGES assertions all sit on subagent spans, never on the turn. emitTeammate itself runs 564 times across the suite, so the path was well exercised but the attribute was simply never checked.

Subagent spans are not part of this gap. The same mutation applied to all three subagent writers produces 25 failures, so that side is already well covered and needs nothing here.

One correction worth recording: my first probe of emitTeammate used a throw and reported zero hits. A catch upstream swallowed it. Re-probing with a filesystem write gave the real 564.

After

Each new assertion now fails under its mutation and passes on real code.

turn-lifecycle          mutated => not ok 1, 10 pass / 1 fail
agent-teams-lifecycle   mutated => not ok 1,  9 pass / 1 fail

Why ahead of the refactor

These pin the current hand-rolled wire format. They pass with src/ byte-identical to main, so the next PR in the stack is provably a no-op on the wire rather than being self-certified by tests written alongside it.

Verification

npm run check

tsc clean, 203/203 pass, and git diff main -- src/ is empty on this branch.

🤖 Generated with Claude Code

[rgao-coreweave]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• refactor(trace): move tool spans onto 0.16.6 end() options #173
• refactor(trace): record output messages through record() #171
• test(trace): cover gen_ai.output.messages on turn and teammate spans #170 👈 (View in Graphite)
• chore(deps): bump weave to 0.16.6 #169
• main

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