[UI] Visual polish and design system consistency

[erikdarlingdata]

Summary

The dark theme is cohesive (8.5/10 color system) but several polish items would elevate the overall quality. Spacing is inconsistent, icons come from mixed sources, charts lack interactivity, and transitions are absent.

Source: Comprehensive themed agent review (UI Designer)

Checklist

Spacing & Layout System

• Define spacing scale resources: SpacingXS=2, SpacingSm=4, SpacingMd=8, SpacingLg=12, SpacingXL=16 (PR Visual polish: MinHeight/MinWidth, spacing resources, InstallerGui theme #128)
• Standardize corner radius: 2px small, 4px medium, 6px large (PR Visual polish: MinHeight/MinWidth, spacing resources, InstallerGui theme #128)
• Replace hardcoded margins/padding with resource references
• Set MinHeight="600" MinWidth="900" on MainWindow (both projects) (PR Visual polish: MinHeight/MinWidth, spacing resources, InstallerGui theme #128)

Tab Overflow

• Handle tab header overflow when many server tabs are open
• Implement ScrollViewer on tab strip or "More tabs" overflow menu
• Increase tab close button target size (currently 18x18, risk of accidental close) (PR Increase tab close button target size (18x18 → 22x22) #129: 18x18 → 22x22)

Charts (ScottPlot)

• Implement data point hover tooltips (exact values on hover) (PR Fix: Add missing hover tooltips to 4 Lite charts (#121) #126 — Lite ChartHoverHelper)
• Move legends outside plot area or add toggle
• Increase grid line opacity for readability on dark background (PR Visual polish: grid lines, sidebar icons, button hover transitions #130: WithAlpha 20→40)
• Consider zoom/pan controls for detailed analysis

DataGrid Improvements

• Right-align numeric columns (CPU, memory, count) for easier comparison
• Make filter-active indicator more obvious (icon + color, not just subtle background)
• Add sort direction indicators (arrows)
• Consider proportional column sizing instead of fixed widths

Icons & Visual Elements

• Unify icon sources (currently mixed: Unicode symbols + Segoe MDL2 + emojis)
• Pick one system (Segoe MDL2 recommended for WPF) and migrate
• Add icons to sidebar buttons (Settings, Help) for visual scanning (PR Visual polish: grid lines, sidebar icons, button hover transitions #130)

Transitions & Feedback

• Add 100-150ms hover transitions on buttons (currently instant) (PR Visual polish: grid lines, sidebar icons, button hover transitions #130: 120ms ColorAnimation)
• Add success confirmation on save/refresh (brief green highlight or toast)
• Replace rotating text spinner (⟳) with proper progress ring

InstallerGui Theme Alignment

• Align InstallerGui colors with Dashboard/Lite theme (#333333 → #181b1f, #404040 → #22252b) (PR Visual polish: MinHeight/MinWidth, spacing resources, InstallerGui theme #128)

Priority

Tier 3 - Medium (spacing, tab overflow, charts), Tier 4 - Low (transitions, icons)