Elysia events report as `sentry.javascript.bun`

Running under both node and bun, with the built `@sentry/elysia`:

```
sdk: {"name":"sentry.javascript.bun","version":"10.67.0",
"packages":[{"name":"npm:@sentry/bun","version":"10.67.0"}]}
```

`sentry.javascript.elysia` never appears. `packages/elysia/src/sdk.ts:44` copies `userOptions` into `options` *before* calling `applySdkMetadata(userOptions, 'elysia', ...)`. When `userOptions._metadata` is undefined, `applySdkMetadata` creates a fresh `_metadata` on `userOptions`, which the already-made copy does not have. `initBun(options)` then applies its own `'bun'` metadata to the copy.

The Elysia SDK is invisible in SDK adoption telemetry, and support cannot tell Elysia reports from plain Bun ones.

**Work item.** Call `applySdkMetadata(options, ...)` on the copy, or move the call above the spread. One-line fix. Add an assertion to `packages/elysia/test` that `event.sdk.name === 'sentry.javascript.elysia'`.

**Prior art** the identical bug was already found and fixed one package over: [#15458]()/[#15459]() "fix(bun): Includes correct sdk metadata". That PR also added the SDK-metadata assertion to the Bun tests, which is the test to copy here.

Inspect packages/elysia/src/sdk.ts around the metadata application and compare the corresponding Bun fix in #15459. Run the tests under packages/elysia/test, then add an assertion that event.sdk.name is sentry.javascript.elysia; done means the assertion passes for the built Elysia SDK.

Do mô hình lập chỉ mục viết ra từ nội dung của issue.