chore: ignore .idea directory in git

[BlackHole1]

[BlackHole1]

I'd argue that either you put this in your global .gitignore, or we ignore all editors' specific directories/files. I'm generally more in favor of the former.

It may not be a good idea to put it globally, as the .idea has a role in some projects (e.g. debug). See: https://github.com/netless-io/flat/blob/main/docs/debugging/electron/README.md#webstorm

Although .idea and .vscode are the same in nature, there are many more files in .idea than in .vscode, which is the main reason why many projects don't put .idea in git.

I can submit another PR to migrate the vscode configuration from the project to the .editorconfig file.