Add streaming support metadata to model schema

[i-need-token]

Context

The AI Models Catalog tracks model capabilities like tool_call, reasoning, structured_output, etc. One important capability that's missing is streaming support — whether a model supports streaming responses.

What to do

1. Add a streaming: boolean optional field to the model schema in types/model.ts
2. Add the Zod validation in types/schemas.ts
3. Update the interactive catalog to show a streaming indicator
4. Update relevant docs (chat-models.md, api.md)

Files to modify

• types/model.ts — add streaming field
• types/schemas.ts — add Zod validation
• site/index.html — add streaming filter/capability badge

Notes

• This is a schema addition only — no provider data changes needed
• Follow the pattern of existing boolean fields like tool_call, reasoning
• Make sure to run npx oxfmt --write before committing