feat(utils): add persona color generation utility

src/lib/utils/personaColors.ts

@@ -0,0 +1,41 @@
+/**
+ * Generate a consistent color for a persona based on their ID
+ * Uses a rainbow spectrum for variety
+ */
+export function getPersonaColor(personaId: string): string {
+	// Simple hash function to get a number from persona ID
+	let hash = 0;
+	for (let i = 0; i < personaId.length; i++) {
+		hash = personaId.charCodeAt(i) + ((hash << 5) - hash);
+		hash = hash & hash; // Convert to 32bit integer
+	}
+
+	// Use hash to pick from a set of distinct colors
+	const colors = [
+		"#ef4444", // red
+		"#f97316", // orange
+		"#f59e0b", // amber
+		"#eab308", // yellow
+		"#84cc16", // lime
+		"#22c55e", // green
+		"#10b981", // emerald
+		"#14b8a6", // teal
+		"#06b6d4", // cyan
+		"#0ea5e9", // sky
+		"#3b82f6", // blue
+		"#6366f1", // indigo
+		"#8b5cf6", // violet
+		"#a855f7", // purple
+		"#d946ef", // fuchsia
+		"#ec4899", // pink
+		"#f43f5e", // rose
+	];
+
+	const index = Math.abs(hash) % colors.length;
+	return colors[index];
+}
+
+/**
+ * User message color
+ */
+export const USER_COLOR = "#9ca3af"; // gray-400