docs: add VitePress documentation site

- Add docs directory with VitePress configuration
- Add GitHub Actions workflow for docs build and deploy
- Support bilingual (English/Chinese) documentation
- Include search, custom theme, and responsive design

docs/scripts/check-index-size.js

@@ -0,0 +1,91 @@
+#!/usr/bin/env node
+
+/**
+ * Search Index Size Checker
+ * Alerts when search index exceeds recommended size for FlexSearch
+ */
+
+import fs from 'node:fs'
+import path from 'node:path'
+import { pathToFileURL } from 'node:url'
+
+const INDEX_PATHS = [
+  path.join(process.cwd(), '.vitepress/dist/search-index.root.json'),
+  path.join(process.cwd(), '.vitepress/dist/search-index.zh.json')
+]
+const MAX_SIZE = 1024 * 1024 // 1MB
+const MAX_DOCS = 2000
+
+function checkIndexSize() {
+  const missing = INDEX_PATHS.filter((p) => !fs.existsSync(p))
+  if (missing.length > 0) {
+    console.log('⚠️  Search index not found. Run build first.')
+    for (const p of missing) console.log(`   Missing: ${p}`)
+    return 1
+  }
+
+  let totalBytes = 0
+  let totalDocs = 0
+
+  console.log(`\n📊 Search Index Analysis`)
+  console.log(`━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━`)
+  for (const indexPath of INDEX_PATHS) {
+    const stats = fs.statSync(indexPath)
+    totalBytes += stats.size
+
+    const sizeKB = (stats.size / 1024).toFixed(2)
+    const sizeMB = (stats.size / (1024 * 1024)).toFixed(2)
+    console.log(`File: ${path.relative(process.cwd(), indexPath)}`)
+    console.log(`Size: ${sizeKB} KB (${sizeMB} MB)`)
+
+    try {
+      const parsed = JSON.parse(fs.readFileSync(indexPath, 'utf-8'))
+      if (Array.isArray(parsed.docs)) {
+        totalDocs += parsed.docs.length
+        console.log(`Docs: ${parsed.docs.length}`)
+      } else {
+        console.log(`Docs: (unknown format)`)
+      }
+    } catch {
+      console.log(`Docs: (unavailable)`)
+    }
+    console.log('')
+  }
+
+  const totalKB = (totalBytes / 1024).toFixed(2)
+  const totalMB = (totalBytes / (1024 * 1024)).toFixed(2)
+  console.log(`Total: ${totalKB} KB (${totalMB} MB)`)
+  console.log(`Total docs: ~${totalDocs}`)
+
+  // Check size threshold
+  if (totalBytes > MAX_SIZE) {
+    console.log(`\n⚠️  WARNING: Index size exceeds ${MAX_SIZE / 1024 / 1024} MB`)
+    console.log(`   Current: ${totalMB} MB`)
+    console.log(`   Impact: Slower search performance`)
+    console.log(`   Recommendation: Consider Algolia DocSearch\n`)
+
+    console.log(`Migration Options:`)
+    console.log(`  1. Apply for Algolia DocSearch (free for open source)`)
+    console.log(`  2. Reduce indexed content`)
+    console.log(`  3. Split documentation into multiple sites\n`)
+
+    return 1
+  }
+
+  if (totalDocs > MAX_DOCS) {
+    console.log(`\n⚠️  WARNING: Indexed docs exceeds ${MAX_DOCS}`)
+    console.log(`   Current: ${totalDocs} docs`)
+    console.log(`   Recommendation: Consider Algolia DocSearch\n`)
+    return 1
+  }
+
+  console.log(`\n✅ Search index is within recommended limits\n`)
+  return 0
+}
+
+// Run if called directly
+if (import.meta.url === pathToFileURL(process.argv[1]).href) {
+  process.exit(checkIndexSize())
+}
+
+export { checkIndexSize }