refactor: improve codebase structure and Univer integration

- Add AGENTS.md knowledge base with project documentation
- Move UserPreferences model to separate models.py file
- Extract API_KEY to environment variable for security
- Enhance Univer Editor with PPTX support and improved UI
- Improve file system handling with binary file detection
- Add HF_ENDPOINT mirror for better China connectivity
- Clean up unused imports and code structure

src/composables/useFileSystem.js

@@ -35,15 +35,20 @@ async function withStore(mode, handler) {
   return new Promise((resolve, reject) => {
     const transaction = db.transaction(STORE_NAME, mode)
     const store = transaction.objectStore(STORE_NAME)
-    let result
+    let request
     try {
-      result = handler(store)
+      request = handler(store)
     } catch (error) {
       reject(error)
       return
     }
-    transaction.oncomplete = () => resolve(result)
-    transaction.onerror = () => reject(transaction.error || new Error('本地数据库写入失败'))
+    if (request && typeof request.onsuccess === 'function') {
+      request.onsuccess = () => resolve(request.result)
+      request.onerror = () => reject(request.error || new Error('本地数据库操作失败'))
+    } else {
+      transaction.oncomplete = () => resolve(request)
+      transaction.onerror = () => reject(transaction.error || new Error('本地数据库操作失败'))
+    }
     transaction.onabort = () => reject(transaction.error || new Error('本地数据库操作已取消'))
   })
 }
@@ -62,43 +67,32 @@ function getExtension(name = '') {
 }
 
 function isTextExtension(ext) {
-  return [
-    'md',
-    'markdown',
-    'txt',
-    'json',
-    'js',
-    'jsx',
-    'ts',
-    'tsx',
-    'css',
-    'scss',
-    'less',
-    'html',
-    'htm',
-    'py',
-    'vue',
-    'xml',
-    'yaml',
-    'yml',
-    'csv',
-    'log',
-    'sql',
-    'toml',
-    'ini',
-    'cfg',
-    'conf',
-    'sh',
-    'bat',
-    'ps1',
-    'java',
-    'c',
-    'cpp',
-    'h',
-    'hpp',
-    'go',
-    'rs'
-  ].includes(ext)
+  const textExtensions = [
+    'md', 'markdown', 'txt', 'json', 'js', 'jsx', 'ts', 'tsx',
+    'css', 'scss', 'less', 'html', 'htm', 'py', 'vue', 'xml',
+    'yaml', 'yml', 'csv', 'log', 'sql', 'toml', 'ini', 'cfg',
+    'conf', 'sh', 'bat', 'ps1', 'java', 'c', 'cpp', 'h', 'hpp',
+    'go', 'rs', 'swift', 'kt', 'rb', 'php', 'pl', 'r', 'scala',
+    'gradle', 'properties', 'env', 'gitignore', 'dockerfile'
+  ]
+  return textExtensions.includes(ext)
+}
+
+function isBinaryExtension(ext) {
+  const binaryExtensions = [
+    'exe', 'dll', 'so', 'dylib', 'bin', 'dat', 'obj', 'o', 'a',
+    'doc', 'docx', 'xls', 'xlsx', 'ppt', 'pptx', 'odt', 'ods', 'odp',
+    'pdf', 'zip', 'rar', '7z', 'tar', 'gz', 'bz2', 'xz',
+    'png', 'jpg', 'jpeg', 'gif', 'bmp', 'ico', 'webp', 'svg',
+    'mp3', 'mp4', 'wav', 'avi', 'mov', 'mkv', 'flv', 'wmv',
+    'ttf', 'otf', 'woff', 'woff2', 'eot',
+    'class', 'pyc', 'pyo', 'jar', 'war', 'ear',
+    'db', 'sqlite', 'mdb', 'accdb',
+    'pem', 'key', 'crt', 'cer', 'p12', 'pfx', 'jks',
+    'msg', 'eml', 'pst', 'ost',
+    'dwg', 'dxf', 'step', 'stl', 'obj', 'fbx', '3ds', 'blend'
+  ]
+  return binaryExtensions.includes(ext.toLowerCase())
 }
 
 function inferMimeType(name, fallback = '') {
@@ -143,6 +137,8 @@ function inferMimeType(name, fallback = '') {
 
 function isTextFile(record) {
   const ext = getExtension(record?.name)
+  // 二进制文件不提供预览
+  if (isBinaryExtension(ext)) return false
   const mime = String(record?.mimeType || '')
   return isTextExtension(ext) || mime.startsWith('text/') || mime.includes('json') || mime.includes('xml')
 }
@@ -218,6 +214,7 @@ async function readFilePayload(file) {
   const mimeType = inferMimeType(file.name, file.type)
   const ext = getExtension(file.name)
   const textFile = isTextExtension(ext) || mimeType.startsWith('text/') || mimeType.includes('json') || mimeType.includes('xml')
+
   if (!textFile) {
     return {
       mimeType,
@@ -226,6 +223,17 @@ async function readFilePayload(file) {
       blob: file
     }
   }
+
+  // 二进制扩展名文件不尝试读取内容，避免长时间等待
+  if (isBinaryExtension(ext)) {
+    return {
+      mimeType,
+      size: file.size,
+      storageKind: 'blob',
+      blob: file
+    }
+  }
+
   if (file.size <= MAX_TEXT_SIZE) {
     const content = await file.text()
     return {
@@ -314,13 +322,8 @@ export function useFileSystem() {
   async function load() {
     loading.value = true
     try {
-      const stored = await withStore('readonly', (store) => store.getAll())
-      const request = stored
-      const nextRecords = await new Promise((resolve, reject) => {
-        request.onsuccess = () => resolve(Array.isArray(request.result) ? request.result : [])
-        request.onerror = () => reject(request.error || new Error('读取本地文件失败'))
-      })
-      if (nextRecords.length === 0) {
+      const nextRecords = await withStore('readonly', (store) => store.getAll())
+      if (!Array.isArray(nextRecords) || nextRecords.length === 0) {
         const seed = createWelcomeRecords()
         await Promise.all(seed.map((record) => persistRecord(record)))
         records.value = seed