feat: enhance PolinePicker with saturation ring controls

- Introduced UI metrics for saturation rings including anchor radius, ring thickness, and tick length.
- Implemented saturation ring rendering around anchor points with hover effects.
- Added rotary interaction for adjusting saturation via mouse drag, supporting shift key for finer control.
- Refactored pointer event handling to support ring adjustments and hover states.
- Updated SVG structure to accommodate new saturation ring elements.
- Removed unused circle creation method to streamline code.

Author: meodai

dist/index.mjs

@@ -517,7 +517,6 @@ var Poline = class {
    * getColorAt(1) // Returns color at the very end
    */
   getColorAt(t) {
-    var _a;
     if (t < 0 || t > 1) {
       throw new Error("Position must be between 0 and 1");
     }
@@ -534,7 +533,7 @@ var Poline = class {
     const pair = this._anchorPairs[actualSegmentIndex];
     if (!pair || pair.length < 2 || !pair[0] || !pair[1]) {
       return new ColorPoint({
-        color: ((_a = this.anchorPoints[0]) == null ? void 0 : _a.color) || [0, 0, 0],
+        color: this.anchorPoints[0]?.color || [0, 0, 0],
         invertedLightness: this._invertedLightness
       });
     }
@@ -585,4 +584,3 @@ export {
   randomHSLPair,
   randomHSLTriple
 };
-//# sourceMappingURL=index.mjs.map