[Studio] Enhance MiniLine/MiniBar chart components

[zhaohai666]

Summary

Upgrade MiniLine from a simple polyline chart to a smooth, animated SVG
component with gradient fill and responsive mode support.

MiniLine enhancements:

• Catmull-Rom → Bézier spline interpolation for smooth curves
• SVG linear gradient fill under the curve
• Animated stroke-dasharray on mount
• Endpoint dot indicator on the last data point
• responsive prop for 100% width with preserved aspect ratio
• Unique gradient/glow IDs per instance to prevent multi-component conflicts
• New optional props: strokeWidth, showDot, animated, responsive
  (all backward-compatible with defaults)

MiniBar fix:

• Remove special-case for zero values; all bars now have minimum 4px height
  for visual consistency

Test plan

• MiniLine renders smooth curves with gradient fill
• Animation plays on mount, no animation when animated=false
• Multiple MiniLine instances on same page have independent gradients
• responsive=true makes SVG fill parent width
• MiniBar: zero-value bars show 4px height (not 0px)