The production LANGUAGE_RUNTIME was a handwritten twin of the tested
LanguageRuntime class (germanDictionary/Pending/Failed): equivalent on the
day it was written, invisible to every i18n-runtime test afterwards. The
registry now exports one page-scoped `new LanguageRuntime(LANGUAGE_REGISTRY,
…)` instance — the whole existing suite starts proving the object production
actually runs, and a contract unit (instanceof + source free of the old
field names) keeps the duplicate from returning.
The class gains an optional `loadFailed(code)` hook — fired once when a
dictionary load settles into English fallback — and the registry fans it out
through `subscribeLanguageLoadFailures`. Only the View card subscribes (it
alone owns toast infrastructure): a failed language pack now shows the new
`toast.locale_load_failed` message (en/ru/de) instead of a console-only
warning; space card and both GUI editors keep the console warning as before.
Proofs: contract unit, hook unit, subscription unit; smoke_german_locale
extended — the both-attempts-failed scenario now asserts the visible toast;
two new registry mutants (handwritten-twin returns, toast dropped).
Issue: #354
User-Visible: yes
A fully fictional house (plans, devices, states) used for README screenshots,
the demo GIF and headless smoke tests — so no real home data ever appears in
public materials.
srv/demo.html — self-contained host page: <ha-icon>/<ha-card> stubs and a
fake hass (registries, states, callWS, callService, floors).
srv/assets/ — generated plan SVGs and icons.js (node demo/gen_icons.mjs,
needs the repo's devDependencies). The card bundle is copied from dist/:
npm run bundle:sync (копия стенда не коммитится, #255).
serve.mjs — playwright launcher (route interception, no web server).
smoke_*.mjs — feature smoke tests; run with a Chromium installed via
PLAYWRIGHT_BROWSERS_PATH=<dir> npx playwright install chromium-headless-shell.
Note for sandboxed sessions: /tmp does not survive; this directory is the
persistent home of the harness (docs/DEVELOPMENT.md has the LD_LIBRARY_PATH recipe).