[chore]: use `unicorn/filename-case` eslint rule

Previously, we discussed the specification of file names (see: https://github.com/netless-io/flat/issues/714)

But this is all built on an ego-driven basis and we need to have a rule to help us check this.

Thanks to @LitoMore recommendation, we were made aware of the existence of unicorn/filename-case.

Rule Link: https://github.com/sindresorhus/eslint-plugin-unicorn/blob/main/docs/rules/filename-case.md

The following rules, which I have just come up with, may not be perfect.

"unicorn/filename-case": [
	"error",
	{
		"cases": {
			"kebabCase": true,
			"ignore": [
				"^[A-Z].+\\.tsx$",
				"^README.*\\.md$",
				".*\\.yaml",
				".*\\.yml"
			],
		}
	}
]