Add sort options to Models list in web console

[GoDiao]

The Models tab currently shows models sorted alphabetically by ID. It would be nice to let users sort by other criteria.

What needs to be done:

Frontend (src/web/static/app.js and src/web/templates/index.html):

• Add a sort dropdown to the Models tab (e.g., "Name", "Context size", "Number of providers")
• Implement client-side sorting in renderModels()

Acceptance criteria:

• Users can sort models by name, context size, and number of providers
• Default sort remains alphabetical