feat(dev): add sample data generator script

Adds a CLI tool to generate realistic analytics data for local development and testing.
Creates two demo websites with varying traffic patterns and realistic user behavior distributions.

scripts/seed/utils.ts

@@ -0,0 +1,85 @@
+import { v4 as uuidv4 } from 'uuid';
+
+export interface WeightedOption<T> {
+  value: T;
+  weight: number;
+}
+
+export function weightedRandom<T>(options: WeightedOption<T>[]): T {
+  const totalWeight = options.reduce((sum, opt) => sum + opt.weight, 0);
+  let random = Math.random() * totalWeight;
+
+  for (const option of options) {
+    random -= option.weight;
+    if (random <= 0) {
+      return option.value;
+    }
+  }
+
+  return options[options.length - 1].value;
+}
+
+export function randomInt(min: number, max: number): number {
+  return Math.floor(Math.random() * (max - min + 1)) + min;
+}
+
+export function randomFloat(min: number, max: number): number {
+  return Math.random() * (max - min) + min;
+}
+
+export function pickRandom<T>(array: T[]): T {
+  return array[Math.floor(Math.random() * array.length)];
+}
+
+export function shuffleArray<T>(array: T[]): T[] {
+  const result = [...array];
+  for (let i = result.length - 1; i > 0; i--) {
+    const j = Math.floor(Math.random() * (i + 1));
+    [result[i], result[j]] = [result[j], result[i]];
+  }
+  return result;
+}
+
+export function uuid(): string {
+  return uuidv4();
+}
+
+export function generateDatesBetween(startDate: Date, endDate: Date): Date[] {
+  const dates: Date[] = [];
+  const current = new Date(startDate);
+  current.setHours(0, 0, 0, 0);
+
+  while (current <= endDate) {
+    dates.push(new Date(current));
+    current.setDate(current.getDate() + 1);
+  }
+
+  return dates;
+}
+
+export function addHours(date: Date, hours: number): Date {
+  return new Date(date.getTime() + hours * 60 * 60 * 1000);
+}
+
+export function addMinutes(date: Date, minutes: number): Date {
+  return new Date(date.getTime() + minutes * 60 * 1000);
+}
+
+export function addSeconds(date: Date, seconds: number): Date {
+  return new Date(date.getTime() + seconds * 1000);
+}
+
+export function subDays(date: Date, days: number): Date {
+  return new Date(date.getTime() - days * 24 * 60 * 60 * 1000);
+}
+
+export function formatNumber(num: number): string {
+  return num.toLocaleString();
+}
+
+export function progressBar(current: number, total: number, width = 30): string {
+  const percent = current / total;
+  const filled = Math.round(width * percent);
+  const empty = width - filled;
+  return `[${'█'.repeat(filled)}${'░'.repeat(empty)}] ${Math.round(percent * 100)}%`;
+}