[codex] Clinical KB cleanup readiness

[BigSimmo]

Summary

• Aligns Clinical KB local runtime policy with CI by pinning Node 22 in .nvmrc, .node-version, package.json, and lockfile metadata.
• Extracts dashboard search retry/fallback/progress/answer-usability helpers into src/components/clinical-dashboard/search-utils.ts with focused unit coverage.
• Stabilizes Chromium browser smoke expectations for local/demo document states and current dashboard labels.
• Removes unused Next starter SVG assets from public/ after confirming no references remain.

Risk Notes

• No Supabase schema, auth, storage, queue, import, enrichment, or cleanup scripts were run.
• Main is treated as the protected/base branch despite no GitHub branch protection.
• The worktree shows Git CRLF/index noise on untouched files locally, but git diff, git diff --cached, and untracked checks are clean.
• The cleanup keeps the larger dashboard/RAG/document-viewer architecture work deferred.

Dependency Changes

• Runtime policy only: Node 22.x and npm >=10 are declared.
• No package version upgrades were made.
• npm ls --depth=0 exits 0 but reports optional wasm/native packages as extraneous; this is carried as a local npm/platform quirk.
• ESLint 10 remains deferred because the repo currently uses ESLint 9.39.4 with eslint-config-next@16.2.7.

Redundancy Removed

• Deleted unused starter assets: public/file.svg, public/globe.svg, public/next.svg, public/vercel.svg, public/window.svg.

Verification Evidence

Local verification under Node 22:

• fnm exec --using 22 cmd /c npm ci passed; 0 vulnerabilities.
• fnm exec --using 22 cmd /c npm ls --depth=0 exited 0.
• fnm exec --using 22 cmd /c npm audit --json passed with 0 vulnerabilities.
• fnm exec --using 22 cmd /c npm run check:supabase-project passed for Clinical KB Database (sjrfecxgysukkwxsowpy).
• fnm exec --using 22 cmd /c npm run format:check passed.
• fnm exec --using 22 cmd /c npm run lint passed after one inspected timeout retry.
• fnm exec --using 22 cmd /c npm run typecheck passed.
• fnm exec --using 22 cmd /c npm run test passed: 39 files, 240 tests.
• fnm exec --using 22 cmd /c npm run build passed.
• git diff --check HEAD -- passed.
• Branch diff secret pattern scan passed.

App/API/browser QA:

• fnm exec --using 22 cmd /c npm run ensure started the guarded local server.
• /api/local-project-id confirmed Clinical KB, project id clinical-kb:5b6a50f62d5b, safe local origin on http://localhost:4298.
• In-app browser smoke loaded the dashboard, confirmed title Clinical KB, rendered clinical dashboard content, and observed 0 console errors.
• fnm exec --using 22 cmd /c npm run test:e2e:chromium passed: 20/20.
• Repo-owned dev server was stopped after QA and port 4298 no longer accepted connections.

Known Deferrals

• ESLint 10 upgrade is deferred until framework/config compatibility is explicitly addressed.
• Larger architecture splits for dashboard, RAG orchestration, document viewer, and oversized tests are deferred.
• Demo/sample corpus cleanup beyond documented ownership is deferred.
• Supabase data/queue/storage cleanup remains out of scope without separate approval.