test(typegen): event-route inputs register the optional preflight key (#664 follow-up) - #670

Closes the last red test on main after #664 (route-register-typegen.test.ts in Verify (integration-2), run 34006833369).

Cause

#664 added preflight?: Preflight to AgentEventRouteProps (and the harness's AgentEventRouteInput), so the generated routes.d.ts registers an event route's input as { canonical, native, preflight? }. The typegen test still asserted keyof RegisteredRouteInput<'event:tool/after'> equals 'canonical' | 'native' — a superseded contract, not a product bug. #664's gate ran the unit pool and three integration files but not this one.

The other five failures from that run (prepack.test.ts ×3, route-invocation-dev-server.test.ts ×2, all from #656) were fixed concurrently by #667 (packed paths resolve from the npm root) and #669 (watcher ignores the package build's .dist.compile- scratch dir). Verified independently here: instrumenting the watcher showed DBG-INVALIDATION [".dist.compile-XXXXXX"] triggering the spurious republish that moved pluginRoot and dropped the operator .env layer.

Change

One assertion in packages/agent-bundle/tests/route-register-typegen.test.ts: the registered event-route input keys are 'canonical' | 'native' | 'preflight'. Plus the matching prose in website/docs/{en,zh}/guide/development/testing.mdx ({ canonical, native, preflight? }). Tests and docs only; skip-changeset.

Local merge gate

Branch contains origin/main at e4c5e26de3 (#669).

pnpm build && pnpm typecheck && pnpm lint && pnpm test:unit     # ok, ok, ok (1432 files, 88 rules), 4272 passed
AGENT_BUNDLE_WORKBENCH_PREBUILT=1 AGENT_BUNDLE_PACKAGE_PREBUILT=1 pnpm exec rstest --config rstest.integration.config.ts \
  packages/agent-bundle/tests/prepack.test.ts \
  packages/agent-bundle/tests/route-register-typegen.test.ts \
  packages/agent-bundle/tests/route-invocation-dev-server.test.ts   # 3 files, 27 passed, 0 failed
pnpm test:packed                                                # 39 passed, 1 skipped (at pre-rebase head bce82913fa; no src change since)
pnpm docs:site:build                                            # ok (language parity, 0 broken links)

Deslop: Claude Fable 5.1, 0 edits (two-line test diff).

Self-review

Reviewer: GPT-5.6 Sol (medium), change-risk-reviewer, against the diff vs origin/main.

• Assertion matches feat(events): pass preflight data to routes #664's contract: typegen omits only signal (src/routes/typegen.ts), production and harness forward preflight — confirmed, no product bug papered over.
• No other shared-contract test asserts the old shape; route-graph.test.ts:1703 uses a fixture-local WorkspaceOpenInput — dismissed.
• website/docs/{en,zh}/guide/development/testing.mdx still said { canonical, native } — fixed in this PR, pnpm docs:site:build green.
• skip-changeset appropriate (tests + website only) — kept.

Second pass after the docs fix: no merge risks found.