Add missing common.loading i18n key to en/ru locales. Add close button
and ESC key support to the overlay spinner so users can cancel running
capture tests. Uses AbortController to abort the in-flight fetch request.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Replace the single 7034-line app.js with 17 ES module files organized
into core/ (state, api, i18n, ui) and features/ (calibration, dashboard,
device-discovery, devices, displays, kc-targets, pattern-templates,
profiles, streams, tabs, targets, tutorials) with an app.js entry point
that registers ~90 onclick globals on window. No bundler needed — FastAPI
serves modules directly via <script type="module">.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
