chore: 移除 LeetCode 笔记并加入站点验证与 Agent 工作流规则

- 从 collections、导航移除 LeetCode，删除 docs/notes/programming/leetcode 下页面

- devDependencies 显式加入 @vuepress/helper@rc.123，配合 overrides 降低 Vite 预构建白屏风险

- 新增 npm run docs:verify 与 scripts/verify-site.mjs（构建后检查首页 hero）

- .cursor/rules/agent-workflow-verify-and-git.mdc：每次修改须验证；用户未明确说不要提交时默认 commit

Made-with: Cursor

scripts/verify-site.mjs

@@ -0,0 +1,27 @@
+import { readFileSync, existsSync } from 'node:fs'
+import { spawnSync } from 'node:child_process'
+import { fileURLToPath } from 'node:url'
+import { dirname, join } from 'node:path'
+
+const root = join(dirname(fileURLToPath(import.meta.url)), '..')
+const indexHtml = join(root, 'docs', '.vuepress', 'dist', 'index.html')
+
+const build = spawnSync('npm', ['run', 'docs:build'], {
+  cwd: root,
+  shell: true,
+  stdio: 'inherit',
+})
+if (build.status !== 0) process.exit(build.status ?? 1)
+
+if (!existsSync(indexHtml)) {
+  console.error('verify-site: dist/index.html missing after build')
+  process.exit(1)
+}
+
+const html = readFileSync(indexHtml, 'utf8')
+if (!html.includes('hero-name') || !html.includes('仲夏夜之梦')) {
+  console.error('verify-site: home hero markers missing in dist/index.html (possible theme/render failure)')
+  process.exit(1)
+}
+
+console.log('verify-site: OK (home hero present in production build)')