refactor(harness): use @decocms/shared/std's sleep in gemini-interactions poll loop

[pedrofrxncx]

Source: C1 reduction — reinvented stdlib. pollInteraction's poll loop (Gemini Deep Research usage/cost tracking path, packages/harness/src/decopilot/gemini-interactions.ts) hand-rolled a new Promise + setTimeout + AbortController sleep instead of using @decocms/shared/std's canonical sleep(ms, { signal }), which is already the established pattern elsewhere in this same package (see liveness-heartbeat.ts, which explicitly calls out this rule from CLAUDE.md/AGENTS.md).

Why a maintainer wants it: one fewer hand-rolled setTimeout/AbortController wait to maintain, consistent with the repo's consolidated async-primitives rule; net line reduction (-11/+7 in the source file).

Behavior preserved: @decocms/shared/std's sleep may reject with a raw AbortSignal.reason (which can be a DOMException, NOT instanceof Error), whereas callers here (and classifyStreamError's error instanceof Error && error.name === "AbortError" check) expect a real Error. The replacement keeps the existing makeAbortError normalization by wrapping the shared sleep call in a .catch() that re-throws through it — so the rejection shape is byte-identical to before in both the pre-aborted and abort-mid-sleep cases.

Regression test: added gemini-interactions.test.ts, which mocks fetch to abort mid-poll and asserts pollInteraction rejects with an Error named "AbortError" — this is the case the manual wrapper exists to guarantee, and it would have caught a naive swap-in of the shared sleep without the normalization.

Reviewer check: bun test packages/harness/src/decopilot/gemini-interactions.test.ts

Locally verified: bun run fmt, cd packages/harness && bunx tsc --noEmit (clean), and the targeted test above (1 pass). Full CI validates the rest.

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Summary by cubic

Replaced the custom sleep in the Gemini interactions poll loop with the shared sleep from @decocms/shared/std, keeping abort behavior identical. Added a regression test to ensure aborts still throw an Error named "AbortError".

• Refactors
  • Use @decocms/shared/std's sleep(ms, { signal }) in pollInteraction instead of a manual Promise/timeout.
  • Catch sleep rejections and rethrow via makeAbortError to preserve the exact Error shape for pre-abort and mid-sleep aborts.

^{Written for commit 4093c05. Summary will update on new commits.}