# DS-002 — Reusable WALKA reference top bar

Status: COMPLETED
Issue: #92
Parent UI Task Master: #85
Implementation branch: `agent/ds-002-reference-top-bar`
Pull request: #98
Stable merge: `1628e17f40543c2f6f60482cb3a90ecd5bd36f45`

## Delivered

- Extracted `WalkaReferenceTopBar` into `mobile/lib/design_system/components/chrome/walka_reference_top_bar.dart`.
- Preserved the released 68px top-bar geometry, 48px leading/trailing slots, WALKA wordmark style, white surface and divider.
- Supports empty, decorative and interactive leading/trailing slots.
- Existing `WalkaReferenceHeader` remains as a compatibility wrapper and delegates to the extracted component.
- Focused widget tests cover centering, slot dimensions, callbacks and compatibility delegation.

## Validation receipt

- PR head: `d8681035b9ee7c37b6882991abb0b531b34bb856`.
- PR workflow: `31387319071` / run #472 — GREEN.
- Flutter Analyze: GREEN.
- Full Flutter tests: GREEN.
- Android runner + WALKA branding: GREEN.
- Release APK: GREEN.
- Candidate artifact: `9062366896`.
- Candidate digest: `sha256:efb4b069561df1ba7fe42349e8e0fdd3389d6ec4e038bd1961d330b9a611a0c9`.
- Stable merge: `1628e17f40543c2f6f60482cb3a90ecd5bd36f45`.
- Combined stable-main validation after DS-002..DS-006: workflow `31388321272` / run #486 — GREEN including release APK publication.
- Combined stable source: `90f59f792b92d4789159f44c2714339f6357b042`.
- Verified APK SHA-256: `c070b853cd6d23bef31b304bce3d0983a6d51e36f9b3726b5fd12cc6705936f2`.

## Guardrails preserved

- Product Master unchanged.
- Navigation/business behavior unchanged.
- Protected `Images/` unchanged.
- No owner-visible visual change introduced by the extraction.