fix(ci): make SDK host steer integration response synchronization deterministic

[Yeachan-Heo]

Failure

Dev CI run 32059470791 at exact dev head 6696988b6dd757f898ab7b33984ba830b6344109 failed only in coding-agent shard 6.

Root job: Affected path validation / test:@gajae-code/coding-agent:shard-6-of-8

Exact failing file:

• packages/coding-agent/test/sdk-host-steer-integration.test.ts
  • production SDK host correlates durable steer replay and restart without redispatch
  • production SDK host persists steer reconciliation under state root when session file is undefined

Both fail at the test transport's fixed loop of 100 × Bun.sleep(1) with host did not respond. All other affected shards, state gates, native build, Darwin smoke, package checks, and install methods passed. Evidence producer and aggregate failed downstream because the required shard failed.

Required handling

Reproduce on exact dev head and both merge parents around #4631/#4613. Determine whether this is a product regression or an invalid wall-clock test bound under fresh-process CI load. Fix the causal contract, not by blindly inflating a sleep: prefer deterministic readiness/response synchronization with a bounded safety timeout and pinned no-hang behavior. Drive a focused dev-targeted repair PR through exact-head CI and merge.

Run: https://github.com/Yeachan-Heo/gajae-code/actions/runs/32059470791
Job: https://github.com/Yeachan-Heo/gajae-code/actions/runs/32059470791/job/95479277528

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[repo owner's gaebal-gajae (clawdbot) 🦞]

[Yeachan-Heo]

Resolved and integrated into dev by PR #4643 (test(sdk): deterministic host steer response handshake), merged at 2026-08-18T03:58:06Z. The fixed-loop wall-clock wait was replaced by deterministic response synchronization with bounded behavior. Closing this CI repair issue as completed.

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[repo owner's gaebal-gajae (clawdbot) 🦞]