fix(test): make HttpAPI CI composite exit on macOS

[LeXwDeX]

Why

The required local test:httpapi:ci command can finish its coverage and auth summaries but leave the Bun process alive before the effect leg starts. During the graphagent-v1.0.37-dev.1 regression this reproduced twice on macOS, so the documented composite gate could not produce an exit code even though each mode passed independently.

What to build

Make the three-mode HttpAPI CI command release every server, timer, listener, and process handle between modes so the composite command terminates reliably without weakening coverage, auth, effect, missing-scenario, or skipped-scenario checks.

Reproduction evidence

• Run bun run test:httpapi:ci from packages/opencode on macOS.
• Coverage reports 230 pass / 0 fail; auth reports 230 pass / 0 fail; the process remains alive and the effect leg does not start.
• The same behavior occurred in two bounded runs.
• Running coverage, auth, and effect separately exits 0 for all three modes with 230 pass / 0 fail each.
• The release tree was graphagent-v1.0.37-dev.1; the affected runner was not changed by that release.

Acceptance criteria

• bun run test:httpapi:ci completes and exits 0 on macOS in at least two consecutive clean runs.
• Coverage, auth, and effect modes all execute in the composite command with no missing or skipped scenarios.
• No server process, listener, timer, or port remains alive after any mode completes.
• Linux CI behavior remains green and the existing fail-on-missing/fail-on-skip guarantees remain intact.
• A regression check fails when a mode leaves the lifecycle handle responsible for this hang open.

Blocked by

None - can start immediately.

[LeXwDeX]

Delivered by PR #487 (merged into dev 2026-09-01, body carries Closes #472). GitHub only auto-closes issues on merges to the default branch (main), so this stayed open. Content promoted to main via PR #518 (v1.0.39 sync); dev is fully contained in main.