centralize the Monitor version and prepare the 1.2.4.2-beta

- centralize the app version in a new `AppImage/lib/version.ts` — the dashboard footer, SMART report footer and release-notes modal all read from a single export, so a future bump only has to touch version.ts, package.json and beta_version.txt
- roll `package.json` and `package-lock.json` to `1.2.4.2-beta` (the lockfile was still stuck on the stale `1.2.2.2-beta` marker)
- move the previous `1.2.4.1-beta` feature list into the modal's historical CHANGELOG under its August 17, 2026 date so navigating "Anterior/Próximo" still walks through the complete history
- write the four new What's New entries for the ongoing 1.2.4.2 cycle: smarter LXC app detection (Docker promoted as parent workload during cold start, unregistered suggestions cached at startup, on-demand catalog scan), end-to-end Docker updates (Engine + per-image tracking on the 24h cycle with a "Check now" action), the 380+ workload detection catalog built from the live community-scripts source, and Pushover joining Telegram/Gotify/Discord/Email/Apprise as a native notification channel
- add the four new i18n keys (appDetection, dockerUpdates, appCatalog, pushover) to all eight bundled locales — en and es curated, the six remaining kept in English until the docs-i18n workflow retranslates them

AppImage/lib/version.ts

@@ -0,0 +1,11 @@
+// Single source of truth for the app version displayed inside the
+// Monitor. Every component that renders the version (dashboard footer,
+// SMART report footer, release-notes modal…) imports from here so a
+// version bump only has to be applied once per file lane:
+//
+//   1. AppImage/lib/version.ts       ← this file
+//   2. AppImage/package.json         ← npm/Next.js metadata
+//   3. beta_version.txt              ← bash pipeline (build_appimage.sh)
+//
+// Keep the three in sync on every bump.
+export const APP_VERSION = "1.2.4.2-beta"