CLDSRV-809: Initialize token bucket with full buffer

Workers now start with bufferSize tokens (default 50) instead of 0,
enabling fail-open behavior at startup when Redis is unavailable.

Previously, new token buckets started empty and required a Redis
refill cycle before allowing any requests. This caused all initial
requests to be throttled until Redis granted tokens.

Author: anurag4DSB

lib/api/apiUtils/rateLimit/tokenBucket.js

@@ -29,9 +29,9 @@ class WorkerTokenBucket {
         this.log = log;
 
         // Token buffer configuration
-        this.tokens = 0;
         this.bufferSize = config.tokenBucketBufferSize || 50; // Max tokens to hold
         this.refillThreshold = config.tokenBucketRefillThreshold || 20; // Trigger refill when below this
+        this.tokens = this.bufferSize; // Start with full buffer for fail-open at startup
 
         // Refill state
         this.refillInProgress = false;

tests/unit/api/apiUtils/rateLimit/tokenBucket.js

@@ -45,9 +45,9 @@ describe('WorkerTokenBucket', () => {
 
             assert.strictEqual(bucket.bucketName, 'test-bucket');
             assert.deepStrictEqual(bucket.limitConfig, { limit: 100 });
-            assert.strictEqual(bucket.tokens, 0);
             assert.strictEqual(bucket.bufferSize, 50);
             assert.strictEqual(bucket.refillThreshold, 20);
+            assert.strictEqual(bucket.tokens, 50); // Starts with full buffer for fail-open
             assert.strictEqual(bucket.refillInProgress, false);
             assert.strictEqual(bucket.refillCount, 0);
         });