fix(isr): ignore interception context on HTML renders

[JamesbbBriz]

Summary

• ignore client-supplied interception context when dispatching plain HTML page renders
• preserve interception context for legitimate RSC navigation and Server Action requests
• lock the real cache-write contract for both fresh HTML capture and stale background regeneration: RSC data lands on rsc:/photos/123:none:none, never a forged intercepted variant
• add a regression test matching Next.js hard-refresh behavior for interception routes

Closes #2780

Tests

• vp test run tests/app-rsc-handler.test.ts tests/app-page-dispatch.test.ts tests/isr-cache.test.ts tests/fetch-cache.test.ts tests/kv-cache-handler.test.ts — 524 passed
• focused fresh/stale cache-key regressions — 2 passed
• vp check on all changed files
• git diff --check

The existing Server Action regression also verifies that legitimate actions retain the raw interception source before the HTML-only dispatch gate.

[JamesbbBriz]

/bigbonk

[pkg-pr-new]

Open in StackBlitz

npm i https://pkg.pr.new/@vinext/cloudflare@2915

npm i https://pkg.pr.new/create-vinext-app@2915

npm i https://pkg.pr.new/@vinext/types@2915

npm i https://pkg.pr.new/vinext@2915

commit: 070bfb0

[github-actions]

Performance benchmarks

Compared 070bfb0 against base a3d1d1d using alternating same-runner rounds. Next.js was unchanged and skipped.

0 improved · 0 regressed · 6 within ±1.5%

Scenario	Framework	Baseline	Current	Change
Client bundle size (gzip)	vinext	135.4 KB	135.4 KB	⚫ -0.0%
Client entry size (gzip)	vinext	122.8 KB	122.8 KB	⚫ -0.0%
Dev server cold start	vinext	2.88 s	2.86 s	⚫ -0.9%
Production build time	vinext	2.99 s	3.00 s	⚫ +0.4%
RSC entry closure size (gzip)	vinext	114.6 KB	114.6 KB	⚫ +0.0%
Server bundle size (gzip)	vinext	194.8 KB	194.8 KB	⚫ +0.0%

View detailed results and traces

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

[JamesbbBriz]

/bigbonk