fix: replace ts-node with tsx for worker scripts

TypeScript 7's CommonJS export no longer populates ts.sys, which
ts-node's config loader depends on, breaking `npm run worker` with
a TypeError. tsx (esbuild-based) doesn't rely on that API and
natively resolves tsconfig.json path aliases, so tsconfig-paths is
also no longer needed.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

worker/cron-check.ts

@@ -22,12 +22,8 @@ if (existsSync(PID_FILE)) {
 }
 
 const child = spawn(
-  'node',
-  [
-    '-r', 'ts-node/register',
-    '-r', 'tsconfig-paths/register',
-    path.join(__dirname, 'index.ts'),
-  ],
+  process.execPath,
+  [require.resolve('tsx/cli'), path.join(__dirname, 'index.ts')],
   { detached: true, stdio: 'ignore' }
 )
 child.unref()