feat: new token count function

app/utils/token.ts

@@ -0,0 +1,22 @@
+export function estimateTokenLength(input: string): number {
+  let tokenLength = 0;
+
+  for (let i = 0; i < input.length; i++) {
+    const charCode = input.charCodeAt(i);
+
+    if (charCode < 128) {
+      // ASCII character
+      if (charCode <= 122 && charCode >= 65) {
+        // a-Z
+        tokenLength += 0.25;
+      } else {
+        tokenLength += 0.5;
+      }
+    } else {
+      // Unicode character
+      tokenLength += 1.5;
+    }
+  }
+
+  return tokenLength;
+}