feat: introduce `tsdown`, support mixed js & ts in codebase #2231

Job	Run time
Lint	1m 7s
build	49s
Test without ESLint Stylistic	0s
Test with ESLint v8	0s
Test	0s
Test with typescript-eslint v7	0s
Test with old ESLint Stylistic	0s
	1m 56s

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