bun: `Bun.serve` has no `ignoreStatusCodes`

`denoServeIntegration` exposes `ignoreStatusCodes` and runs `processHttpServerTransactionEvent`; `httpServerSpansIntegration` does the same on Node. `bunServerIntegration` has no options at all, so 301/302/401/404 transactions are all recorded on Bun.

**Work item.** Add `ignoreStatusCodes` to `bunServerIntegration`, defaulting to `DEFAULT_IGNORE_STATUS_CODES`, and add the `processEvent` hook.

**Prior art ***(related history only)*. No issue for Bun. The Deno equivalents shipped as getsentry/sentry-javascript#23313 and getsentry/sentry-javascript#23692 (both merged), which aligned `denoHttpIntegration` options with `httpIntegration`. Bun was not part of either.

Start at bunServerIntegration and compare its options and transaction handling with denoServeIntegration and httpServerSpansIntegration. Trace DEFAULT_IGNORE_STATUS_CODES and the processEvent hook, then verify that Bun supports configuring ignored status codes and no longer records the specified status-code transactions by default.

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