feat(build): add transport-neutral worker stages

[james-elicx]

Summary

• split App and Pages Worker handling into request and response stages
• expose transport-neutral stage contracts and lazy virtual entry loaders
• keep middleware, config routing, and request-specific composition above reusable response rendering
• preserve single-stage behavior when no staged output is selected
• isolate render dependencies from the request-stage startup graph

This layer contains no Cloudflare RPC, Worker export, Wrangler, or HTTP transport implementation.

Stack

1. tooling baseline (chore(deps): update Cloudflare Workers tooling #3082)
2. This PR: transport-neutral worker stages (feat(build): add transport-neutral worker stages #3083)
3. Cloudflare Workers Cache entrypoint isolation (feat(cloudflare): isolate Workers Cache with staged entrypoints #3079)
4. independently deployed HTTP stages (feat(build): support independently deployed worker stages #3084)
5. Workers Cache tag parity (fix(cloudflare): preserve Workers Cache tag parity #3085)

Validation

• CI: all 68 checks passed
• 846 focused core/config tests passed locally
• vp run vinext#build
• Knip

[pkg-pr-new]

Open in StackBlitz

npm i https://pkg.pr.new/@vinext/cloudflare@3083

npm i https://pkg.pr.new/create-vinext-app@3083

npm i https://pkg.pr.new/@vinext/types@3083

npm i https://pkg.pr.new/vinext@3083

commit: eacb78d

[github-actions]

Example	Preview	Production	Original
app-router-cloudflare	preview	production
pages-router-cloudflare	preview	production
app-router-playground	preview	production	original
realworld-api-rest	preview	production
nextra-docs-template	preview	production
benchmarks	preview	production
hackernews	preview	production	original
workers-cache	preview	production
web	preview	production

[github-actions]

Performance benchmarks

Compared eacb78d against base 110ef06 using alternating same-runner rounds. Next.js was unchanged and skipped.

0 improved · 4 regressed · 2 within ±1.5%

Scenario	Framework	Baseline	Current	Change
Client bundle size (gzip)	vinext	142.2 KB	142.2 KB	⚫ +0.0%
Client entry size (gzip)	vinext	129.5 KB	129.5 KB	⚫ +0.0%
Dev server cold start	vinext	3.03 s	3.15 s	🔴 +4.0%
Production build time	vinext	3.33 s	3.39 s	🔴 +1.7%
RSC entry closure size (gzip)	vinext	116.6 KB	121.1 KB	🔴 +3.9%
Server bundle size (gzip)	vinext	198.1 KB	205.0 KB	🔴 +3.5%

View detailed results and traces

_{🟢 improvement · 🔴 regression · ⚫ change below 1.5% · paired base/head}