feat: say the backend is starting instead of claiming it is broken - #7
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The packaged backend needs a couple of seconds on a warm launch and ~20s on the first launch after an install. During that window every API call failed with "could not reach the backend", which reads as broken, not starting - the message told users to go check on a backend that was doing exactly what it should. The backend gains GET /api/health, and a slim top banner polls it once a second until it answers: "Connecting to the CSEMInsight backend... (Ns)". Past 45s it adds the honest explanation - a first launch can take half a minute, and beyond that the backend at the shown address may genuinely have failed. The banner never renders in demo mode (no backend exists), before the first probe answers, or after the backend is up, so a dev session with the backend already running never sees it. Polling stops for good once ready; a backend dying later is reported by the failing call itself. Note: the local full-suite frontend run currently flakes on three pre-existing TriangleModelWindow timeouts under parallel load (they fail on clean main too, pass in isolation and in CI); tracked separately. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
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The last piece of the startup plan (#4, #6). The packaged backend needs ~2s on a warm launch and ~20s on the first launch after an install — and during that window every API call failed with "could not reach the backend", telling users to go check on a backend that was doing exactly what it should.
What it does
GET /api/health(two tests, including the CORS preflight).When it stays invisible
Six tests cover: immediate-ready renders nothing, banner while down, clears on recovery, long-wait hint, demo-mode silence, and polling stops after ready.
Verification
bun run buildclean.TriangleModelWindowtimeouts under parallel load. Verified on cleanmain(3 failed / 265 passed there too); they pass in isolation and CI has been green. Tracked as a separate task.🤖 Generated with Claude Code