App Router: middleware-rewritten shallow link breaks history traversal

This issue was created by an agent analysing CI failures from the Next.js Deploy Suite (vinext main vs Next.js v16.2.6, 2026-05-22).

Problem

After a middleware-rewritten navigation, the back button ([data-go-back]) never becomes visible, indicating the rewritten page never finishes rendering or history state isn't wired up. May relate to the canonical-URL handling from #1348.

[data-go-back] never visible after middleware-rewritten navigation

Estimated Impact

~1 test failures across the deploy suite.

Affected Test Suites

• test/e2e/middleware-shallow-link/index.test.ts

Recommendation

1. Reproduce first in vinext's own test suite. Use the middleware-shallow-link fixture and assert the back button appears after the rewrite.

2. Investigate the navigation commit path. After a middleware rewrite, the canonical URL must be set in the history entry and the page must finish rendering.

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Part of #1328.