fix: strip trailing slash in SigV4 canonical URI

AWS SigV4 canonical URI must not have trailing slash (except root '/').
Bun can receive paths with trailing slash from SDK, causing signature
mismatch for all bucket operations (CreateBucket, HeadBucket, etc.)

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

src/utils/s3/auth.ts

@@ -1,5 +1,4 @@
 import { timingSafeEqual } from 'node:crypto';
-import logger from '../../shared/logger/index';
 
 /**
  * Timing-safe string comparison that prevents timing attacks.
@@ -167,9 +166,9 @@ const normalizeUri = (uri: string): string => {
     result.push(segment);
   }
 
-  // Reconstruct path
+  // Reconstruct path (no trailing slash except root)
   const normalized = result.length > 0 ? `/${result.join('/')}` : '/';
-  return normalized;
+  return normalized === '/' ? '/' : normalized.replace(/\/+$/, '');
 };
 
 const awsEncode = (value: string): string =>
@@ -300,15 +299,6 @@ export const verifySignature = async (
 
   const hashedCanonicalRequest = await sha256Hex(canonicalRequest);
 
-  // Debug canonical request for non-root GETs (bucket operations)
-  logger.info('SigV4 canonical request', {
-    method,
-    path: parsedUrl.pathname,
-    signedHeaders: parsed.signedHeaders,
-    hashedPayload: hashedPayload.slice(0, 20) + '...',
-    canReq: canonicalRequest.slice(0, 500),
-  });
-
   // M1: Fall back to Date header if x-amz-date is missing
   const amzDate = headers['x-amz-date'] || headers['date'] || '';