photoanalyzer/delivery_backlog/stories/US02-05-frontend-shell.md

US02-05 — Build the Static Application Shell

Epic: E02

As a user, I want a fast, navigable application shell so all workflow views share one consistent interface without server-generated operational HTML.

Acceptance criteria

• index.html, CSS, and modular JavaScript are separate static files.
• Shared API client, store, router, error handling, cancellation, and SSE/polling adapters are implemented.
• Navigation routes restore current view and filters after reload.
• HTML fallback never intercepts /api/v1 requests.

Automated tests

• JavaScript tests cover API errors, store transitions, routing, and event fallback.
• Browser tests assert asset loading, deep links, reload, JSON-only APIs, and no unexpected console/network errors.

Dependencies

• US02-04