[codex] Make dashboard sailfish logo prominent

[futeng]

What changed

• stop shrinking the full circular application icon into the dashboard header
• draw a dedicated fixed sailfish brand silhouette for the dashboard
• remove the dominant outer ring
• expand the sailfish to a stable 72×48 frame so its long bill, sail fin, forked tail, and lower fins remain visible
• keep the logo independent from network state and menu bar character settings

Validation

• swift test --package-path NetPulse: 24 tests passed
• installed and launched /Users/futeng/Applications/NetPulse.app
• visually inspected the real dashboard window
• confirmed the sailfish occupies the primary logo area without overlapping the title or summary