Add frontend support for HNSW-based visualization

[Thebinary110]

Summary

This PR adds frontend support for an HNSW-based visualization method in the VisualizeChart component.

Motivation

Current visualization options (t-SNE / PCA) do not scale well for large collections.
An HNSW-based approach allows fast, index-aware visualization and is a good fit
for large vector datasets.

Scope

• UI-only change
• No backend changes
• Existing visualization methods remain unchanged

Implementation details

• Extended request handling to support a new hnsw visualization method
• Reused existing rendering, color, and size logic
• Feature is opt-in and does not affect current workflows

Notes

The /collections/{collection}/visualize endpoint is not yet implemented in Qdrant core.
Until backend support is added, the request fails gracefully without impacting the UI.

Related

Closes #108

[Thebinary110]

This endpoint doesn’t exist yet, why add this?
I need backend to implement Vector fetch feature