fix: improve update workflow visibility and reload behavior

[alexk-dev]

Summary

• redesign the dashboard updates experience around an explicit workflow with progress, stage labels, target/current metadata, clearer CTAs, and automatic page reload when the backend comes back after restart
• extend the backend update status contract with target/progress/stage fields, keep failed update attempts visible to the UI, and run update-now asynchronously so stage changes are observable instead of collapsing into a single opaque action
• normalize packaged -exec versions so the updater stops offering no-op updates to the same version, and improve diagnostics/sidebar update indicators to reflect the new state model

[sonarqubecloud]

Quality Gate failed

Failed conditions
71.4% Coverage on New Code (required ≥ 80%)

See analysis details on SonarQube Cloud