fix(utils): improve validation error messages for clarity

Co-authored-by: BioPhoton <10064416+BioPhoton@users.noreply.github.com>

Author: Copilot

packages/utils/src/lib/wal-sharded.ts

@@ -43,14 +43,12 @@ function validateGroupId(groupId: string): void {
 
   // Reject path separators (both forward and backward slashes)
   if (groupId.includes('/') || groupId.includes('\\')) {
-    throw new Error(
-      'groupId cannot contain path separators (/ or \\): path traversal detected',
-    );
+    throw new Error('groupId cannot contain path separators (/ or \\)');
   }
 
   // Reject relative path components
   if (groupId === '..' || groupId === '.') {
-    throw new Error('groupId cannot be "." or "..": path traversal detected');
+    throw new Error('groupId cannot be "." or ".."');
   }
 
   // Reject null bytes which can be used to bypass validation

packages/utils/src/lib/wal-sharded.unit.test.ts

@@ -77,13 +77,13 @@ describe('ShardedWal', () => {
   describe('path traversal validation', () => {
     it('should reject groupId with forward slashes', () => {
       expect(() => getShardedWal({ groupId: '../etc/passwd' })).toThrow(
-        'groupId cannot contain path separators',
+        'groupId cannot contain path separators (/ or \\)',
       );
     });
 
     it('should reject groupId with backward slashes', () => {
       expect(() => getShardedWal({ groupId: '..\\windows\\system32' })).toThrow(
-        'groupId cannot contain path separators',
+        'groupId cannot contain path separators (/ or \\)',
       );
     });
 
@@ -134,7 +134,7 @@ describe('ShardedWal', () => {
         getShardedWal({
           measureNameEnvVar: 'CP_PROFILER_MEASURE_NAME',
         }),
-      ).toThrow('groupId cannot contain path separators');
+      ).toThrow('groupId cannot contain path separators (/ or \\)');
     });
   });