Unify Omni web navbar rendering across all web surfaces.
Problem:
- different pages/apps render slightly different top nav menus,
- items vary depending on which page/app is being viewed.
Implement:
- extract navbar rendering to a shared library module,
- update each web surface to use that shared navbar renderer,
- ensure consistent top-level menu items everywhere.
Acceptance:
- /tasks, /news, /pipeline, and /files pages share identical top navbar structure/items,
- no duplicated navbar item lists across app-specific modules.
Implemented unified navbar extraction. Added Omni/Web/Nav.hs as shared top-nav renderer and updated Task/Web + WebStyle consumers to use it. Deployed web; verified /tasks, /news/, /pipeline/, /files/ all render identical primary nav links: /tasks /pipeline/ /news/ /files/ /stats. Evidence: _/tmp/proof-t-676.md