feat: introduce `tsdown`, support mixed js & ts in codebase #2197

Job	Run time
Lint	51s
Test (21)	38s
Test (18)	39s
Test (lts/*)	53s
Test (20)	43s
Test without ESLint Stylistic	2m 12s
Test with ESLint v8	55s
Test with old ESLint Stylistic (3)	2m 12s
Test with old ESLint Stylistic (4)	2m 19s
Test with old ESLint Stylistic (2)	2m 22s
Test with typescript-eslint v7	2m 18s
	16m 2s

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