perf: lazy-load document pdf viewer

[BigSimmo]

Summary

• Deferred pdf-canvas-viewer loading in src/components/DocumentViewer.tsx behind next/dynamic() so PDF-specific code is fetched only when a PDF is rendered.
• Added an accessible PDF loading fallback during the dynamic chunk load.
• Added/kept a regression test in tests/document-viewer-pdf-reader-lazy.test.ts to ensure the PDF viewer imports remain outside the initial document client chunk.

Verification

• ./node_modules/.bin/vitest run tests/document-viewer-pdf-reader-lazy.test.ts --reporter=dot (pass)
• npm run verify:cheap (blocked: docs/site-map.md is stale; no sitemap update included in this PR)
• npm run verify:ui not run: environment-level font/network constraint prevents stable local UI run in this task context.
• UI verification not run: local browser + ensure path could not complete due external resource fetch issues in this environment.

Clinical Governance Preflight

Not required. This change is limited to frontend bundle loading behavior in the document viewer and does not affect ingestion, answer generation, source rendering, clinical logic, or privacy-sensitive pathways.

Risk and rollout

Low-risk UI performance optimization. Behavior remains the same for PDF rendering, with a loading placeholder added for the lazy-loaded chunk; no new clinical logic or data-flow changes.

[supabase]

This pull request has been ignored for the connected project sjrfecxgysukkwxsowpy because there are no changes detected in supabase directory. You can change this behaviour in Project Integrations Settings ↗︎.

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[coderabbitai]

📝 Walkthrough

Walkthrough

PDF preview components now load through client-only dynamic imports, using a shared accessible loading indicator while the PDF reader becomes available.

Changes

PDF viewer loading

Layer / File(s)	Summary
Dynamic PDF viewer integration src/components/DocumentViewer.tsx	PdfCanvasViewer and NativePdfEmbed are dynamically imported with server-side rendering disabled and share an accessible “Loading PDF reader…” fallback.

Estimated code review effort: 1 (Trivial) | ~5 minutes

Possibly related PRs

• BigSimmo/Database#509: Refactors the related PDF preview UI in DocumentViewer.tsx.
• BigSimmo/Database#750: Makes the same PDF viewer imports client-only with a shared loading fallback.
• BigSimmo/Database#763: Updates the same PDF viewer imports and loading fallback.

Suggested labels: codex

Suggested reviewers: claude, copilot

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Title check	✅ Passed	The title concisely reflects the main change: lazily loading the document PDF viewer for performance.
Description check	✅ Passed	The description covers Summary, Verification, Clinical Governance Preflight, and Risk/Rollout, with only the Notes section left blank.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch codex/frontend-document-viewer-lazy-20260718-clean

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[github-actions]

CI triage

CI failed on this PR. Automated classification of the 6 failed job(s):

• Unit coverage — needs investigation: inspect the failing step and uploaded diagnostics; rerun only after classifying the cause.
• Static PR checks — needs investigation: inspect the failing step and uploaded diagnostics; rerun only after classifying the cause.
• Production UI — needs investigation: inspect the failing step and uploaded diagnostics; rerun only after classifying the cause.
• Build — needs investigation: inspect the failing step and uploaded diagnostics; rerun only after classifying the cause.
• Advisory UI — needs investigation: inspect the failing step and uploaded diagnostics; rerun only after classifying the cause.
• PR required — needs investigation: inspect the failing step and uploaded diagnostics; rerun only after classifying the cause.

Compared with main CI run #3205 (success).

Classification is evidence routing, not permission to ignore a failure. Exact quarantined Playwright identities remain governed by the flake ledger.