fix(core): reuse runtime World for route handlers

[MintedKenny]

Description

Fixes #3665.

workflowEntrypoint() now initializes its request-time queue handler from getWorld() instead of getWorldHandlers(). This makes route initialization and subsequent runtime operations share one process-level World instance.

The public getWorldHandlers() API, its signature, and its intentionally separate build-time-safe cache are unchanged.

Previously, route initialization populated the handler-only cache and the first runtime operation independently populated the runtime cache. Stateful async World factories could therefore create duplicate database pools, listeners, queue workers, or similar process-scoped resources.

How did you test your changes?

• Added a regression test with an async World factory that initializes a workflow route and then calls getWorld().
• Confirmed the regression test fails on the prior implementation because the factory is called twice.
• Confirmed the focused regression test passes after the change.
• Ran the complete @workflow/core suite on Node 24: 101 test files passed, 1 skipped; 2,180 tests passed, 3 expected failures, 1 skipped.
• Ran @workflow/core typechecking successfully.
• Ran the documentation link validator successfully.
• Ran Biome formatting and lint checks; lint completed with the repository's existing advisory warnings and no errors attributable to this change.

The full documentation code-sample harness requires built workspace package declarations. The partial local build cannot produce every package because the SWC package requires a Rust toolchain that is not installed; CI remains the authoritative full-workspace result.

Docs Preview

Vercel did not produce an accessible workflow-docs preview for this fork PR: its deployment checks require Vercel Labs authorization. The changed v5 routes are:

• /v5/docs/api-reference/workflow-runtime/workflow-entrypoint
• /v5/docs/api-reference/workflow-runtime/get-world-handlers

PR Checklist - Required to merge

• 📦 pnpm changeset was run to create a patch changelog for this PR
• 🔒 DCO sign-off passes (git commit --signoff)
• 📝 Ping @vercel/workflow once the PR is ready for review

[changeset-bot]

🦋 Changeset detected

Latest commit: 77b28b8

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 16 packages

Name	Type
workflow	Patch
@workflow/core	Patch
@workflow/world-testing	Patch
@workflow/builders	Patch
@workflow/cli	Patch
@workflow/next	Patch
@workflow/nitro	Patch
@workflow/vitest	Patch
@workflow/web-shared	Patch
@workflow/web	Patch
@workflow/astro	Patch
@workflow/nest	Patch
@workflow/rollup	Patch
@workflow/sveltekit	Patch
@workflow/vite	Patch
@workflow/nuxt	Patch

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