Refine header and footer scroll timing

[BigSimmo]

Summary

• require deliberate scroll travel before the shared header and phone composer hide or reveal
• reset accumulated intent when direction, active state, or responsive behavior changes
• align hide/show timing and easing while preserving reduced-motion behavior
• add focused unit coverage for thresholds, accumulation, and direction changes

Verification

• npm run verify:pr-local — not completed: its verify:cheap unit phase hit the existing 30-second repository graph-scan timeout under local disk contention after format, lint, and TypeScript passed
• npm run verify:ui — full suite not repeated; the five directly affected Chromium cases passed
• npm run verify:release — not run; no provider-backed or broad release workflow was invoked

Completed locally:

• npm test -- --run tests/use-hide-on-scroll.test.ts — 7/7 passed on the final rebased commit
• focused Chromium UI smoke (ui-smoke.spec.ts, header/composer grep) — 5/5 passed
• scoped ESLint — passed
• Prettier — passed
• full TypeScript and full lint stages from verify:cheap — passed
• git diff --check origin/main..HEAD — passed

Clinical Governance Preflight

Not applicable. This change is limited to local UI scroll timing and does not touch ingestion, answer generation, retrieval/ranking, sources, document access, privacy, production environment, or clinical output.

Notes

• The browser proof used the repo-supported webpack dev path because Turbopack rejects the clean verification worktree's external node_modules junction.
• No Supabase, OpenAI, live-provider, or production-like checks were run.

Summary by CodeRabbit

• New Features

  • Improved hide-on-scroll behavior for headers and bottom composers by requiring deliberate scrolling before hiding or revealing them.
  • Added direction-aware handling that resets intent when scrolling changes direction.
  • Refined animation timing for smoother show and hide transitions.

• Bug Fixes

  • Preserved existing reduced-motion, responsive breakpoint, and overscroll behavior.
  • Prevented small scroll movements from unexpectedly changing interface visibility.

• Tests

  • Expanded coverage for scroll direction, travel thresholds, reveal behavior, and overscroll handling.

[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]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro Plus

Run ID: d7b3e3f0-b1a1-4164-8dcf-ed8d83bc14e3

📥 Commits

Reviewing files that changed from the base of the PR and between 561cefe and 42461a3.

📒 Files selected for processing (4)

• docs/branch-review-ledger.md
• src/components/clinical-dashboard/master-search-header.tsx
• src/components/clinical-dashboard/use-hide-on-scroll.ts
• tests/use-hide-on-scroll.test.ts

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📝 Walkthrough

Walkthrough

The scroll-hide computation now tracks directional travel before hiding or revealing chrome. The search header and composers use state-dependent transition timing and easing, with tests covering thresholds, reversals, overscroll, and small deltas.

Changes

Scroll chrome behavior

Layer / File(s)	Summary
Directional scroll intent state src/components/clinical-dashboard/use-hide-on-scroll.ts	computeScrollHideUpdate returns and accumulates direction/travel state, while the reporter persists and resets it.
Scroll intent validation tests/use-hide-on-scroll.test.ts	Tests cover deliberate hide/reveal travel, direction changes, top overscroll, sub-threshold deltas, and the expanded return contract.
Header and composer transition timing src/components/clinical-dashboard/master-search-header.tsx, docs/branch-review-ledger.md	Header, bottom-composer, and collapse transitions use conditional 200ms/240ms timing and easing; the ledger records the change and validation results.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Sequence Diagram(s)

sequenceDiagram
  participant User
  participant ScrollReporter
  participant computeScrollHideUpdate
  participant SearchHeader
  User->>ScrollReporter: scroll
  ScrollReporter->>computeScrollHideUpdate: offset and directional travel
  computeScrollHideUpdate-->>ScrollReporter: hidden state and updated intent
  ScrollReporter->>SearchHeader: header/composer visibility state
  SearchHeader->>SearchHeader: apply show or hide transition timing

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Possibly related PRs

• BigSimmo/Database#421: Connects hide-on-scroll behavior to the main content scroll container and related header/composer plumbing.
• BigSimmo/Database#578: Adds related reset behavior for hide-on-scroll state when allowAllBreakpoints changes.

Suggested reviewers: cursoragent

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title matches the main change: scroll timing refinements for the shared header and bottom composer.
Description check	✅ Passed	The description covers the required Summary and Verification sections and includes the relevant completed and skipped checks.
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.

✨ 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/header-footer-scroll-timing-20260717

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