重构：Wails升级/mermaid主题切换/代码高亮修复/文件系统UI重构

- Wails v2.12.0升级（App绑定新增API、runtime类型扩展）
- 修复mermaid暗色主题切换渲染失败（SVG textContent污染→data-mermaid-src保存源码）
- 修复代码高亮全语言失效（languageMap静态白名单替代运行时hljs检查）
- 文件系统：FileListPanel重写、FileItemRow合并删除、Toolbar简化
- 新增剪贴板图片粘贴（Ctrl+V粘贴图片到当前目录）
- 死代码清理：DeviceTest/errorHandler/useLocalStorage移除
- MarkdownEditor优化、theme store增强、CodeMirror加载器精简

web/src/utils/codemirrorExports.js

@@ -10,22 +10,4 @@ export { defaultKeymap, history, historyKeymap } from '@codemirror/commands'
 export { bracketMatching, defaultHighlightStyle, syntaxHighlighting, StreamLanguage } from '@codemirror/language'
 export { oneDark } from '@codemirror/theme-one-dark'
 
-// Language packages
-export { javascript } from '@codemirror/lang-javascript'
-export { json } from '@codemirror/lang-json'
-export { yaml } from '@codemirror/lang-yaml'
-export { html } from '@codemirror/lang-html'
-export { css } from '@codemirror/lang-css'
-export { cpp } from '@codemirror/lang-cpp'
-export { rust } from '@codemirror/lang-rust'
-export { go } from '@codemirror/lang-go'
-export { python } from '@codemirror/lang-python'
-export { php } from '@codemirror/lang-php'
-export { sql } from '@codemirror/lang-sql'
-export { markdown } from '@codemirror/lang-markdown'
-export { java } from '@codemirror/lang-java'
-
-// Legacy language modes (shell, powershell, dart)
-export { shell } from '@codemirror/legacy-modes/mode/shell'
-export { powerShell } from '@codemirror/legacy-modes/mode/powershell'
-export { dart } from '@codemirror/legacy-modes/mode/clike'
+// 语言包通过 codeMirrorLoader 动态导入，避免全量打包