Replaces the build-time VITE_API_BASE knob with a runtime setup screen so
one build works same-origin and cross-origin:
- frontend/src/lib/backend.ts stores the API origin in localStorage
(empty = same origin). DEFAULT_BACKEND_URL is the clearly marked,
easily edited prefilled default — the matrix.org equivalent; set it to
your public API origin.
- Production builds show /setup before anything else on first start,
with a connection test against /health (or leave it blank for this
server). The route stays reachable from Account -> Backend connection;
switching backends clears the previous backend's token and reloads.
- Input normalisation: scheme defaulted (https, http for localhost),
trailing slashes trimmed; a failed cross-origin test points at
CORS_ALLOWED_ORIGINS.
- Dev keeps defaulting to the same-origin Vite proxy; /setup can be
visited manually.
Verified: normalisation cases in Node, /health returns CORS headers for
an allowed origin, tsc/oxlint/build clean.
JakeBreath
a93500154c