feat: add current file actions to title bar

[Liu8Can]

Summary

• add current file actions in the title bar for revealing the current document in its folder and copying the full path
• polish the top chrome by turning the menu into a floating panel and extending the tab context menu with the same file actions
• add the Electron bridge handlers needed for folder reveal and clipboard writes

Testing

• pnpm run build
• pnpm exec oxfmt --check src/preload.ts src/renderer/global.d.ts src/main/ipcBridge.ts src/renderer/components/menu/TitleBar.vue src/renderer/components/menu/MenuDropDown.vue src/renderer/components/workspace/TabBar.vue
• pnpm exec oxlint src/preload.ts src/renderer/global.d.ts src/main/ipcBridge.ts src/renderer/components/menu/TitleBar.vue src/renderer/components/menu/MenuDropDown.vue src/renderer/components/workspace/TabBar.vue

Notes

• the focused issue is 打开的md 能在顶部那里弄个打开文档所在文件夹功能吗 #217
• the repo still has pre-existing oxlint warnings in src/main/ipcBridge.ts outside this change set