refactor: Simplify named colors map in _getRGBA

Simplify the `namedColors` map in `src/dotwave.js` by storing only the RGB string values instead of the entire string format. Extracted alpha string interpolation to the point of function return.

Co-authored-by: jsem-nerad <88319121+jsem-nerad@users.noreply.github.com>

Author: google-labs-jules[bot]

src/dotwave.js

@@ -534,34 +534,34 @@
 
         // For named colors, use a predefined map
         const namedColors = {
-            'white': 'rgba(255, 255, 255, ' + alpha + ')',
-            'black': 'rgba(0, 0, 0, ' + alpha + ')',
-            'red': 'rgba(255, 0, 0, ' + alpha + ')',
-            'green': 'rgba(0, 128, 0, ' + alpha + ')',
-            'blue': 'rgba(0, 0, 255, ' + alpha + ')',
-            'yellow': 'rgba(255, 255, 0, ' + alpha + ')',
-            'orange': 'rgba(255, 165, 0, ' + alpha + ')',
-            'purple': 'rgba(128, 0, 128, ' + alpha + ')',
-            'pink': 'rgba(255, 192, 203, ' + alpha + ')',
-            'brown': 'rgba(165, 42, 42, ' + alpha + ')',
-            'gray': 'rgba(128, 128, 128, ' + alpha + ')',
-            'grey': 'rgba(128, 128, 128, ' + alpha + ')',
-            'cyan': 'rgba(0, 255, 255, ' + alpha + ')',
-            'magenta': 'rgba(255, 0, 255, ' + alpha + ')',
-            'lime': 'rgba(0, 255, 0, ' + alpha + ')',
-            'maroon': 'rgba(128, 0, 0, ' + alpha + ')',
-            'navy': 'rgba(0, 0, 128, ' + alpha + ')',
-            'olive': 'rgba(128, 128, 0, ' + alpha + ')',
-            'teal': 'rgba(0, 128, 128, ' + alpha + ')',
-            'silver': 'rgba(192, 192, 192, ' + alpha + ')',
-            'gold': 'rgba(255, 215, 0, ' + alpha + ')',
-            'indigo': 'rgba(75, 0, 130, ' + alpha + ')',
-            'violet': 'rgba(238, 130, 238, ' + alpha + ')',
-            'turquoise': 'rgba(64, 224, 208, ' + alpha + ')'
+            'white': '255, 255, 255',
+            'black': '0, 0, 0',
+            'red': '255, 0, 0',
+            'green': '0, 128, 0',
+            'blue': '0, 0, 255',
+            'yellow': '255, 255, 0',
+            'orange': '255, 165, 0',
+            'purple': '128, 0, 128',
+            'pink': '255, 192, 203',
+            'brown': '165, 42, 42',
+            'gray': '128, 128, 128',
+            'grey': '128, 128, 128',
+            'cyan': '0, 255, 255',
+            'magenta': '255, 0, 255',
+            'lime': '0, 255, 0',
+            'maroon': '128, 0, 0',
+            'navy': '0, 0, 128',
+            'olive': '128, 128, 0',
+            'teal': '0, 128, 128',
+            'silver': '192, 192, 192',
+            'gold': '255, 215, 0',
+            'indigo': '75, 0, 130',
+            'violet': '238, 130, 238',
+            'turquoise': '64, 224, 208'
         };
-
 
-        return namedColors[color.toLowerCase()] || `rgba(255, 255, 255, ${alpha})`;
+        const namedColor = namedColors[color.toLowerCase()];
+        return namedColor ? `rgba(${namedColor}, ${alpha})` : `rgba(255, 255, 255, ${alpha})`;
     };
 
     /**