refactor: 改用 execSync

Dockerfile

@@ -1,6 +1,6 @@
 FROM alpine
 
-RUN apk add --no-cache nodejs npm git \
+RUN apk add --no-cache bash nodejs npm git \
     && node --version \
     && npm --version \
     && git --version

app/git.js

@@ -1,12 +1,9 @@
-import { spawnSync } from 'child_process';
+import { execSync } from 'child_process';
 import path from 'path';
 import { GITEA_SERVER_URL, GITEA_REPOSITORY, GITEA_TOKEN, PR_HEAD_BRANCH, FINDINGS_PATH } from './config.js';
 
 function git(args, cwd) {
-  const result = spawnSync('git', args, { cwd, encoding: 'utf8' });
-  if (result.error) throw result.error;
-  if (result.status !== 0) throw new Error((result.stderr || result.stdout || '').trim());
-  return (result.stdout || '').trim();
+  return execSync(`git ${args.map(a => `'${a.replace(/'/g, "'\\''")}'`).join(' ')}`, { cwd, encoding: 'utf8' }).trim();
 }
 
 export async function commitAndPush(workspace) {