fix: convert HSL color generation to hex format in label selector

Update generateRandomColor to return hex codes instead of HSL strings
to ensure proper color storage in database.

Changes:
- Add hslToHex conversion function
- Maintain same pastel color generation (random hue, 70% saturation, 65% lightness)
- Return hex format (#rrggbb) instead of HSL string

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

src/components/Common/AutocompleteLabelSelector.tsx

@@ -21,10 +21,24 @@ interface Props {
   scope: 'actors' | 'relations';
 }
 
+// Convert HSL to Hex
+const hslToHex = (h: number, s: number, l: number): string => {
+  l /= 100;
+  const a = (s * Math.min(l, 1 - l)) / 100;
+  const f = (n: number) => {
+    const k = (n + h / 30) % 12;
+    const color = l - a * Math.max(Math.min(k - 3, 9 - k, 1), -1);
+    return Math.round(255 * color)
+      .toString(16)
+      .padStart(2, '0');
+  };
+  return `#${f(0)}${f(8)}${f(4)}`;
+};
+
 // Generate random pastel color for new labels
 const generateRandomColor = () => {
   const hue = Math.floor(Math.random() * 360);
-  return `hsl(${hue}, 70%, 65%)`;
+  return hslToHex(hue, 70, 65);
 };
 
 const AutocompleteLabelSelector = ({ value, onChange, scope }: Props) => {