fix: serve prerendered data for trailing slash routes

[fhammerschmidt]

Context

Search results use the site's canonical trailing-slash URLs. React Router 8 requests /page/_.data when navigating to those URLs, but prerendering currently emits only /page.data. Cloudflare serves HTML for the missing data path, causing the turbo-stream decode error.

Changes

• Copy prerendered route data to matching trailing-slash data paths during the build.
• Preserve the canonical page URLs and the existing non-trailing-slash data files.

Verification

• fnm exec --using 26.3.0 yarn build:vite
• Verified that the two data files for a documentation route are byte-identical in both build/client and out.
• Verified with a local Cloudflare Pages preview that both data paths return 200 with application/octet-stream, while the page URL still redirects to its trailing-slash form.

Fixes #1382

This PR carries the same commit as #1383 on a branch in the rescript-lang repository and can supersede it.

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-09-29T16:39:54.533619Z	3d7a445	Manual request

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[fhammerschmidt]

@codex review

[cloudflare-workers-and-pages]

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Status	Name	Latest Commit	Preview URL	Updated (UTC)
✅ Deployment successful! View logs	guide	3d7a445	Commit Preview URL Branch Preview URL	Sep 29 2026, 04:36 PM

[github-actions]

Docs preview

[chatgpt-codex-connector]

Codex Review: Didn't find any major issues. Keep them coming!

Reviewed commit: 3d7a44567b

ℹ️ About Codex in GitHub

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• Comment "@codex review".

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[github-actions]

Lighthouse baseline

Compared with target branch master at commit 9b534e2. Scores are the median of 3 runs against the deployed Cloudflare preview.

Category	Target	Current	Change
Performance	80	88	+8
Accessibility	80	80	0
Best practices	100	100	0
SEO	92	58	-34

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_{Commit ae85637 · Cloudflare preview}