Reporting errors through a Sentry Java Agent

### Problem Statement

We rely on other libraries to offer some callbacks or require users to manipulate / wrap libraries for errors to be reported to Sentry. By using a Java Agent we could wrap calls and capture errors where there's no clean API to usually do so. We already do something similar for Android using sentry-android-gradle-plugin.

### Solution Brainstorm

A Sentry Java Agent similar to the OTEL agent. Maybe we can combine them so we don't have to figure out how to make them co-exist. Or we could offer a separate agent just for errors which uses common code that we can also leverage in the Sentry OTEL Java Agent.

先閱讀現有的 sentry-android-gradle-plugin 作法，以及 issue 中提到的 Sentry OTEL Java Agent。比較它們如何從沒有 callback API 的函式庫中擷取錯誤，並釐清預期結果是獨立的錯誤回報 agent，還是與 OTEL agent 的整合。該 issue 沒有定義進入點、測試或具體的完成標準。

由索引模型根據 Issue 內容生成。