Add more Cursor rules files about SDK topics

### Description

We have an [overview file](https://github.com/getsentry/sentry-java/blob/main/.cursor/rules/overview_dev.mdc) for Cursor (and other AI).

It's a sort of index file that's always applied to Cursors context. Cursor should then load more detailed rules files mentioned in the overview file based on your prompt.

The intent is to have AI be as helpful as possible while occupying minimal tokens by only loading what's needed.

For the future I was planning on adding more rules files as we go and touch certain areas of the SDK / implement new features. If there's specific rules files you think would help you, please comment here.

從 .cursor/rules/overview_dev.mdc 開始，檢查它如何為 SDK 索引指引內容。選擇一個值得撰寫詳細 Cursor 規則檔案的具體 SDK 主題，新增指引內容，並從概覽中連結到該檔案；當相關 prompt 能夠找到這些新規則時，即表示完成。

由索引模型根據 Issue 內容生成。