Multiple independent requests that fail with the same message (e.g.
Activities.tsx's mount effect firing loadFirstPage/listWorkoutKinds/getProfile
separately) each call showError() independently, previously stacking
2-3 textually-identical banners for a single root cause (backend down,
brief network blip). show() now skips adding a banner if one with the
same severity+message is already visible, and skips scheduling a
redundant auto-dismiss timer for it -- the original banner's timer
keeps running untouched.
A plain module-level singleton store (banner.ts) plus a single renderer
(BannerStack, mounted once above LoginGate in main.tsx) -- no React
Context, since this codebase has none today and a plain exported
function is callable from anywhere, including api/client.ts (a plain
module, not a component) in a later task. Nothing calls it yet; that's
each of this plan's remaining tasks.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
