helper sync overwrites hook-handler.cjs test surface (require.main guard + exports) — make the sync preserve it or test it

**Observed (2026-09-05 mission review, verified):** `a5f86ad0a` ("chore: sync repo dogfood helpers to 3.23.0", 2026-07-04) replaced both copies of `hook-handler.cjs` (repo `.claude/helpers/` and `v3/@claude-flow/cli/.claude/helpers/`) with the packaged build and silently dropped what `cb1e93e8d` (2026-06-15) had added for `tests/hook-handler-runwithtimeout.test.cjs`: the `if (require.main === module)` guard around `main()` and `module.exports = { runWithTimeout, INTELLIGENCE_TIMEOUT_MS }`. Requiring the helper from a test then ran `main()` (stdin read + `process.exit`) and exposed nothing — `runWithTimeout is not a function`.

Nobody noticed for two months because the Test Suite job could not run: root `npm ci` died at `ETARGET` on `@claude-flow/mcp@3.0.0-alpha.10` from 2026-08-22 until #3203. The failure surfaced on the first PR runs after that fix (#3177, #3184) and is restored in #3204.

**Ask:** whichever path produces the "sync dogfood helpers" commits (release tooling or a manual copy) must either (a) carry the guard + exports in the packaged source so a sync cannot drop them, or (b) run `node --test tests/hook-handler-runwithtimeout.test.cjs` as part of the sync/release gate so a regression fails before commit. (a) is already true after #3204 if the packaged copy is the source of the next sync; this issue tracks confirming that and adding (b).

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https://claude.ai/code/session_019xHM4rAH4aaShb4DTr1n6s

Compare .claude/helpers/hook-handler.cjs with v3/@claude-flow/cli/.claude/helpers/hook-handler.cjs and inspect the packaged source or sync entry point that produces them. Run node --test tests/hook-handler-runwithtimeout.test.cjs first. Done means synchronization preserves the require.main guard and exports, and the test runs in the sync or release gate.

Written by the indexing model from the issue text.