RDoc-3913 Vector search performance optimizations

[Danielle9897]

Issue link

https://issues.hibernatingrhinos.com/issue/RDoc-3913/Vector-search-performance-optimizations

Additional description

• Documented how parallel HNSW graph construction can affect vector-search result repeatability.
• Explained RavenDB’s handling of concurrently indexed vectors and the throughput/repeatability trade-off.
• Expanded the configuration reference for MaximumConcurrentBatchesForHnswAcceleration.
• Added cross-links from the C#, Node.js, and Python static-index and dynamic-query articles.
• Configuration refresh and re-indexing behavior is tracked separately as a server issue => RavenDB-27269

Type of change

• Content - docs
• Content - cloud
• Content - guides
• Content - start pages/other
• New docs feature (consider updating /templates or readme)
• Bug fix
• Optimization
• Other

Changes in docs URLs

• No changes in docs URLs
• Articles are restructured, URLs will change, mapping is required (update /scripts/redirects.json file, set Documents Moved PR label)

Changes in UX/UI

• No changes in UX/UI
• Changes in UX/UI (include screenshots and description)