Fixed two issues causing Hugo warnings about duplicate menu entries:
1. Path generation bug: apiPathToSlug returns 'api/v3/...' for paths
starting with '/api/', but the generator always prepended 'api/',
creating 'api/api/v3/...' paths.
Fix: Only add 'api/' prefix if path doesn't already start with it.
2. Config inconsistency: cloud-dedicated, cloud-serverless, and clustered
had '/api' in pagesDir while core/enterprise didn't. The function
always adds '/api', causing double prefixes for some products.
Fix: Removed '/api' from pagesDir for affected products to match
core/enterprise pattern.
f3c841167b