perf: build backend with swc (#9463)

* feat: build backend with swc

* fix: swc build target

Co-authored-by: syuilo <Syuilotan@yahoo.co.jp>

packages/backend/watch.mjs

@@ -1,23 +0,0 @@
-import { execa } from 'execa';
-
-(async () => {
-	// なぜかchokidarが動かない影響で、watchされない
-	/*
-	execa('tsc-alias', ['-w', '-p', 'tsconfig.json'], {
-		stdout: process.stdout,
-		stderr: process.stderr,
-	});
-	*/
-
-	setInterval(() => {
-		execa('tsc-alias', ['-p', 'tsconfig.json'], {
-			stdout: process.stdout,
-			stderr: process.stderr,
-		});
-	}, 3000);
-
-	execa('tsc', ['-w', '-p', 'tsconfig.json'], {
-		stdout: process.stdout,
-		stderr: process.stderr,
-	});
-})();