chore(react):start porting note map

apps/client/src/widgets/note_map/utils.ts

@@ -0,0 +1,6 @@
+export function rgb2hex(rgb: string) {
+    return `#${(rgb.match(/^rgb\((\d+),\s*(\d+),\s*(\d+)\)$/) || [])
+        .slice(1)
+        .map((n) => parseInt(n, 10).toString(16).padStart(2, "0"))
+        .join("")}`;
+}