🎨 Palette: Add dynamic labels and tooltips to MenuBar buttons

[acebytes]

💡 What: Added .help() tooltips to the 'Scan', 'Quick Clean', and 'Docker Prune' buttons in the MenuBar to explain their disabled states, and added dynamic labels (e.g., 'Scanning...', 'Running...') during async execution.
🎯 Why: Previously, these buttons would disable during operations without context, leaving users unsure why they couldn't interact. Dynamic labels provide immediate feedback, and tooltips improve discoverability for disabled states.
📸 Before/After: Visual text change from 'Scan' to 'Scanning...' and 'Run' to 'Running...' while operations execute, plus hover tooltips.
♿ Accessibility: Tooltips (.help()) provide VoiceOver context for why the buttons are unavailable, improving screen reader experience during async tasks.

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PR created automatically by Jules for task 2514293613039685317 started by @acebytes

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