Backport #2110: feat(nitro): add /_workflow web ui during dev

[github-actions]

Automated backport of #2110 to stable (backport job run).

AI recommendation: This is a self-contained minor feature addition to @workflow/nitro that adds a dev-only /_workflow route. Both packages/nitro (with its addVirtualHandler and nitro.routing infrastructure) and packages/web (including the ./server export it depends on) exist on stable, so the change should apply cleanly and provides useful dev-mode functionality on the GA channel.

Merge conflicts were resolved by AI (opencode with anthropic/claude-opus-4.7). Please review the conflict resolution carefully before merging.

[changeset-bot]

🦋 Changeset detected

Latest commit: 1c708c0

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

This PR includes changesets to release 16 packages

Name	Type
@workflow/nitro	Minor
@workflow/nuxt	Patch
workflow	Patch
@workflow/world-testing	Patch
@workflow/core	Patch
@workflow/builders	Patch
@workflow/cli	Patch
@workflow/next	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

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Project	Deployment	Actions	Updated (UTC)
example-nextjs-workflow-turbopack	Ready	Preview, Comment	Jun 2, 2026 1:50pm
example-nextjs-workflow-webpack	Ready	Preview, Comment	Jun 2, 2026 1:50pm
example-workflow	Ready	Preview, Comment	Jun 2, 2026 1:50pm
workbench-astro-workflow	Ready	Preview, Comment	Jun 2, 2026 1:50pm
workbench-express-workflow	Ready	Preview, Comment	Jun 2, 2026 1:50pm
workbench-fastify-workflow	Ready	Preview, Comment	Jun 2, 2026 1:50pm
workbench-hono-workflow	Ready	Preview, Comment	Jun 2, 2026 1:50pm
workbench-nitro-workflow	Ready	Preview, Comment	Jun 2, 2026 1:50pm
workbench-nuxt-workflow	Ready	Preview, Comment	Jun 2, 2026 1:50pm
workbench-sveltekit-workflow	Ready	Preview, Comment	Jun 2, 2026 1:50pm
workbench-tanstack-start-workflow	Ready	Preview, Comment	Jun 2, 2026 1:50pm
workbench-vite-workflow	Ready	Preview, Comment	Jun 2, 2026 1:50pm
workflow-docs	Ready	Preview, Comment, Open in v0	Jun 2, 2026 1:50pm
workflow-swc-playground	Ready	Preview, Comment	Jun 2, 2026 1:50pm
workflow-tarballs	Ready	Preview, Comment	Jun 2, 2026 1:50pm
workflow-web	Ready	Preview, Comment	Jun 2, 2026 1:50pm

[TooTallNate]

Approve — AI-resolved conflicts hold up, faithful backport

This is a backport of #2110 (Nitro dev-mode /_workflow dashboard route) to stable. The backport bot called out that conflicts were AI-resolved; I went through the diff carefully and the resolution is correct.

Byte-identical to original

• Changeset ✓ byte-identical
• package.json ✓ adds @workflow/web: workspace:* dependency identically
• addDashboardHandler function body ✓ byte-identical (the createRequire lookup, the pathToFileURL URL wrapping, the lazy server start with promise caching, the two routing API variants with fromWebHandler wrapping for the old one)

Stable-shape adaptations

The diff against stable differs from main in exactly two places, both for sound reasons:

1. Import line: stable doesn't already have fileURLToPath imported, so the backport adds a fresh import { pathToFileURL } from 'node:url'; line. Main has fileURLToPath already, so its diff added pathToFileURL to the existing import. Same effective import.

2. Regex change skipped: The original PR removed web|web-shared from a regex pattern in main's isWorkflowPkg check. That regex doesn't exist on stable (it's a main-only addition from another PR for SWC workflow package detection). So skipping it is correct — there's nothing to update.

After stripping these two adaptation differences, the additions are byte-identical between the original and backport.

Verified locally

• pnpm install --frozen-lockfile ✓
• pnpm turbo run build --filter @workflow/nitro ✓
• pnpm turbo run typecheck --filter @workflow/nitro ✓

Dependency sanity check

• @workflow/web/server exports startServer(port) on stable ✓ (verified origin/stable:packages/web/server.js)
• @workflow/web is in the workspace and a workspace dep gets added correctly

CI

CI doesn't show the Tests workflow runs yet — only deployments + DCO + Socket Security pass (21 checks). The PR was opened ~16 minutes ago by the github-actions[bot]; Tests may need a manual approval or just hasn't triggered yet. Worth verifying CI runs before merge but no functional issues from the diff itself.

Bottom line

Faithful backport. The dev-only /_workflow redirect lets Nitro projects access the workflow web UI in development without a separate pnpm workflow web command. Useful quality-of-life feature now on the GA channel. Approving.