ArSubsv Lean Engineering UI

ArSubsv is an engineering tool, not a dashboard. The lean UI keeps only the primary work surfaces visible:

• SV Explorer on the left for stream selection.
• Waveform as the dominant center workspace.
• Phasor as a persistent right-side workspace.
• Values, frame metadata, diagnostics, and cursor compare remain available as secondary tabs.

The metric card row was removed. Runtime counters are shown in a compact bottom status bar so the main space remains dedicated to SV waveform and phasor verification.