bun: `Bun.serve` does not support streaming responses

`wrapRequestHandler` in `packages/bun/src/integrations/bunserver.ts:189` uses `startSpan`, which ends the span as soon as the handler returns. Deno (`streamResponse`) and Cloudflare (`classifyResponseStreaming` plus a `TransformStream`) both keep the span open until the body finishes.

An SSE or LLM streaming route on Bun reports a span duration covering only the handler, not the stream. This is the common shape for AI apps, which are a large part of the Bun audience.

**Work item.** Move `classifyResponseStreaming` into `@sentry/core` or `@sentry/server-utils` (see D10) and adopt it in `bunserver.ts` with `startSpanManual`.

Comece em packages/bun/src/integrations/bunserver.ts:189, em wrapRequestHandler, e compare as implementações de Deno streamResponse e Cloudflare classifyResponseStreaming e TransformStream. Revise a proposta D10 para posicionar classifyResponseStreaming e, em seguida, verifique com uma resposta em streaming se o span permanece aberto até o término do body, em vez de terminar quando o handler retorna.

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