fix(mod_custom): make base64ts bundle output deterministic and clean up generated temp sourcemaps

test/test.ts

@@ -1,5 +1,6 @@
 import { expect, tap } from '@git.zone/tstest/tapbundle';
 import * as tsbundle from '../dist_ts/index.js';
+import { CustomBundleHandler } from '../dist_ts/mod_custom/index.js';
 import * as path from 'path';
 import * as fs from 'fs';
 
@@ -61,6 +62,30 @@ tap.test('should bundle with rspack in production mode', async () => {
   await testBundler('rspack', 'production');
 });
 
+tap.test('should generate deterministic base64ts output', async () => {
+  const testDir = path.join(process.cwd(), 'test');
+  const outputPath = path.join(testDir, 'dist_manual/base64-output.ts');
+  const bundleConfig = {
+    from: './ts_web/index.ts',
+    to: './dist_manual/base64-output.ts',
+    outputMode: 'base64ts' as const,
+    bundler: 'esbuild' as const,
+  };
+
+  const handler = new CustomBundleHandler(testDir);
+  if (fs.existsSync(outputPath)) {
+    fs.rmSync(outputPath, { force: true });
+  }
+
+  await handler.processSingleBundle(bundleConfig);
+  const firstOutput = fs.readFileSync(outputPath, 'utf8');
+
+  await handler.processSingleBundle(bundleConfig);
+  const secondOutput = fs.readFileSync(outputPath, 'utf8');
+
+  expect(secondOutput).toEqual(firstOutput);
+});
+
 // Test size comparison
 tap.test('should show bundle size comparison', async () => {
   const testDir = path.join(process.cwd(), 'test');