fix(cache): preserve staged cache invalidation parity

[james-elicx]

Part 14 of 16 in the staged CDN adapter stack. Depends on #3153.

Summary

• preserves canonical invalidation tags through Vary-based cache-key expansion and clean-EOF admission
• tags Pages HTML/data responses consistently and purges regenerated response variants after revalidation
• keeps staged caches partitioned by public authority during invalidation
• extends App, Pages, and Cloudflare adapter regression coverage

Validation

• focused cache, revalidation, request-pipeline, and Cloudflare adapter tests
• PPR cacheability E2E: 8 passed
• cumulative exact-tip changed-test sweep: 3,461 passed, 2 skipped

Review size

• Implementation: +121 / -37 LOC
• Tests and fixtures: +440 / -48 LOC
• Other (docs, config, lockfile): +0 / -0 LOC
• 19 changed files

Measured against codex/cdn-v2-cloudflare-prewarm after rebasing onto main@a6931c0.

[pkg-pr-new]

Open in StackBlitz

npm i https://pkg.pr.new/@vinext/cloudflare@3158

npm i https://pkg.pr.new/create-vinext-app@3158

npm i https://pkg.pr.new/@vinext/types@3158

npm i https://pkg.pr.new/vinext@3158

commit: c6d223d

[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
static-export	preview	production
web	preview	production

[github-actions]

Performance benchmarks

Compared c6d223d against base a4f1d69 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	142.3 KB	142.4 KB	⚫ +0.0%
Client entry size (gzip)	vinext	129.6 KB	129.6 KB	⚫ +0.0%
Dev server cold start	vinext	3.22 s	3.22 s	⚫ -0.1%
Production build time	vinext	3.43 s	3.42 s	⚫ -0.4%
RSC entry closure size (gzip)	vinext	125.6 KB	125.5 KB	⚫ -0.1%
Server bundle size (gzip)	vinext	216.4 KB	216.2 KB	⚫ -0.1%

View detailed results and traces

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