Read `.claude/rules`

Describe the feature or problem you'd like to solve

We use both Claude and CoPilot and we currently need to duplicate instructions between .github/instructions/**/*.instructions.md and .claude/rules

Proposed solution

Support reading .claude/rules. Perhaps also .agents/rules - hopefully we can move to a vendor agnostic location for these files at some point.

If you already read them, then update the documentation here where it is not mentioned that these locations are read: https://docs.github.com/en/copilot/how-tos/copilot-cli/customize-copilot/add-custom-instructions

Example prompts or workflows

No response

Additional context

No response

首先追踪自定义指令位置是如何被发现的，然后检查是否已经读取 .claude/rules，以及 .agents/rules 可以放在哪个位置。将行为与 .github/instructions/**/*.instructions.md 进行比较，并查阅链接的 Copilot 文档；当已支持的位置得到处理，或文档准确列出已经支持的位置时，即表示完成。