chore(ui): project selection does not persist across pages #311

What

Each dashboard page (Issues, Performance, Release Health, Rules) has its own project <select> that defaults to the first project. Selecting demo-app in Issues, then opening Performance, resets the selector back to the default project — the user must re-select on every page.

Suggested fix

Persist the selected project slug (localStorage, or a shared store like the existing auth store pattern), and/or make pages accept ?project= consistently so navigation preserves context. Issues page already round-trips ?project= in its own URL — extend that behavior across pages.

Notes

Found during mobile-view work (PR #306); behavior identical on desktop. Login endpoint also requires the email field (not username) even though first-run setup accepts a username — possibly related API/UX inconsistency worth a look.