feat: integrate Sentry for error tracking and enhance user notifications

- Added Sentry integration for error tracking across various components, including error boundaries and user actions.
- Updated global error handling to capture exceptions and provide detailed feedback to users.
- Enhanced user notifications with toast messages for actions such as credit management, image generation, and canvas exports.
- Improved user experience by displaying relevant messages during interactions, ensuring better visibility of system states and errors.

lib/rate-limit.ts

@@ -0,0 +1,16 @@
+import { redis } from "./redis";
+
+export async function rateLimit(
+  key: string,
+  limit: number,
+  windowSeconds: number
+): Promise<{ success: boolean; remaining: number }> {
+  const count = await redis.incr(key);
+  if (count === 1) {
+    await redis.expire(key, windowSeconds);
+  }
+  return {
+    success: count <= limit,
+    remaining: Math.max(0, limit - count),
+  };
+}