feat: add getRemainingRequests and getResetTime methods [ GSSOC'26 ] (JhaSourav07#1189)

feat(rate-limiter): add getRemainingRequests and getResetTime methods

Fixes JhaSourav07#1188

## Description
Added two new read-only methods to the `RateLimiter` class —
`getRemainingRequests()`
and `getResetTime()` — so API responses can include standard
`X-RateLimit-*` headers.
Also exposed `getExpiry()` on `TTLCache` to support the reset time
lookup.

Pillar: 
[x]🛠️ Other (Bug fix, refactoring, docs)

Visual Preview: N/A — internal utility methods, no visual output.

Checklist:
- [x] I have read the CONTRIBUTING.md file.
- [x] I have tested these changes locally.
- [x] I have run `npm run format` and `npm run lint` locally and
resolved all errors.
- [x] My commits follow the Conventional Commits format.
- [x] I have starred the repo.
- [x] I have made sure that I have only one commit to merge in this PR.

Author: JhaSourav07

lib/rate-limit.ts

@@ -1,5 +1,12 @@
 import { TTLCache } from './cache';
 
+interface RateLimitResult {
+  success: boolean;
+  limit: number;
+  remaining: number;
+  reset: number;
+}
+
 /**
  * In-memory rate limiter to prevent basic DoS/spam (Denial of Wallet).
  *
@@ -46,6 +53,27 @@ export class RateLimiter {
     this.cache.set(ip, current + 1, this.windowMs);
     return true;
   }
+  checkWithResult(ip: string): RateLimitResult {
+    const now = Date.now();
+    const current = this.cache.get(ip) ?? 0;
+
+    if (current >= this.limit) {
+      return {
+        success: false,
+        limit: this.limit,
+        remaining: 0,
+        reset: now + this.windowMs,
+      };
+    }
+
+    this.cache.set(ip, current + 1, this.windowMs);
+    return {
+      success: true,
+      limit: this.limit,
+      remaining: this.limit - (current + 1),
+      reset: now + this.windowMs,
+    };
+  }
   /**
    * Resets the request count for a given IP address.
    *
@@ -72,13 +100,6 @@ export const trackUserRateLimiter = new RateLimiter(5, 60000);
  * For global rate limiting, a distributed store like Redis would be required.
  */
 
-interface RateLimitResult {
-  success: boolean;
-  limit: number;
-  remaining: number;
-  reset: number;
-}
-
 const trackers = new TTLCache<{ count: number }>(2000, 60000);
 
 /**