Decide hybrid SDK API marker for v9

As we mark more SDK surface `@ApiStatus.Internal` ahead of v9 package moves, some types/methods are still consumed by hybrid SDKs (Flutter, React Native, etc.) even when they are not customer-facing.

`@ApiStatus.Internal` alone does not distinguish hybrid-facing surface from pure SDK plumbing, so hybrid consumers can be broken by a later relocate/remove pass.

Known examples called out during review of the utils Internal pass:

* `io.sentry.util.LoadClass`
* `io.sentry.util.TracingUtils`

Context: NoOp stubs and most util helpers were recently marked Internal (getsentry/sentry-java#6016, getsentry/sentry-java#6017); hybrids were explicitly left unmarked for now.

Action taken on behalf of Nelson Osacky.

先檢視 getsentry/sentry-java#6016 和 #6017 中參照的內部標記變更，重點關注 io.sentry.util.LoadClass 和 io.sentry.util.TracingUtils。比較 NoOp stub、util helper 和混合式 SDK consumer 的處理方式，接著定義並套用一項標記政策，以區分面向混合式使用情境的 surface 與純 SDK plumbing。

由索引模型根據 Issue 內容生成。