🏦 refactor: Centralize Caching & Redis Key Prefixing (#8457)

* 🔧 Overhauled caching feature:
- Refactored caching logic.
- Fixed redis prefix, namespace, tls, ttl, and cluster.
- Added REDIS_KEY_PREFIX_VAR

* # refactor: Rename redisCache to standardCache

* # Add Redis pinging mechanism to maintain connection.

* # docs: Add warning about Keyv Redis client prefix support

api/server/middleware/limiters/sttLimiters.js

@@ -1,10 +1,7 @@
 const rateLimit = require('express-rate-limit');
-const { RedisStore } = require('rate-limit-redis');
 const { ViolationTypes } = require('librechat-data-provider');
-const ioredisClient = require('~/cache/ioredisClient');
+const { limiterCache } = require('~/cache/cacheFactory');
 const logViolation = require('~/cache/logViolation');
-const { isEnabled } = require('~/server/utils');
-const { logger } = require('~/config');
 
 const getEnvironmentVariables = () => {
   const STT_IP_MAX = parseInt(process.env.STT_IP_MAX) || 100;
@@ -57,6 +54,7 @@ const createSTTLimiters = () => {
     windowMs: sttIpWindowMs,
     max: sttIpMax,
     handler: createSTTHandler(),
+    store: limiterCache('stt_ip_limiter'),
   };
 
   const userLimiterOptions = {
@@ -66,23 +64,9 @@ const createSTTLimiters = () => {
     keyGenerator: function (req) {
       return req.user?.id; // Use the user ID or NULL if not available
     },
+    store: limiterCache('stt_user_limiter'),
   };
 
-  if (isEnabled(process.env.USE_REDIS) && ioredisClient) {
-    logger.debug('Using Redis for STT rate limiters.');
-    const sendCommand = (...args) => ioredisClient.call(...args);
-    const ipStore = new RedisStore({
-      sendCommand,
-      prefix: 'stt_ip_limiter:',
-    });
-    const userStore = new RedisStore({
-      sendCommand,
-      prefix: 'stt_user_limiter:',
-    });
-    ipLimiterOptions.store = ipStore;
-    userLimiterOptions.store = userStore;
-  }
-
   const sttIpLimiter = rateLimit(ipLimiterOptions);
   const sttUserLimiter = rateLimit(userLimiterOptions);