test(settings): split the settings spec along the facade seams (#1277)

settings.component.spec.ts was 1516 lines and the last settings file in the
max-lines baseline. The behaviour that moved into facades now has its own
specs, driven directly instead of through the rendered page.

- settings-app-update.facade.spec.ts: status polling/retry, bridge actions,
  release notes dialog, version messaging, dispose
- settings-epg.facade.spec.ts: refresh, clear flow, post-save re-fetch
- settings-playlist-reset.facade.spec.ts: summary, dialog, Electron progress,
  browser fallback, failure snackbar
- settings-backup.facade.spec.ts: desktop export, browser download fallback
- settings.component.spec.ts keeps the page shell, the facade lifecycle seam
  and runtime capabilities; settings.component.form.spec.ts takes hydration,
  section outputs, dashboard controls and submit
- settings-section-scroll.directive.spec.ts gives the directive its first spec
- shared TestBed fixtures live in settings/test-stubs/, kept out of both the
  app build (.stub.ts) and the coverage ratchet (test-stubs/)

105 settings tests, up from 94; every file is under the 400-line limit, so
settings.component.spec.ts leaves the baseline.

tools/eslint/max-lines-baseline.mjs

@@ -44,7 +44,6 @@ export const maxLinesBaseline = [
     'apps/web-e2e/src/xtream.e2e.ts',
     'apps/web/src/app/services/electron.service.ts',
     'apps/web/src/app/services/pwa.service.ts',
-    'apps/web/src/app/settings/settings.component.spec.ts',
     'apps/xtream-mock-server/src/app/generators/marketing.generator.ts',
     'libs/epg/data-access/src/lib/epg.service.spec.ts',
     'libs/epg/data-access/src/lib/epg.service.ts',