feat: add file browser and file download with multi-backend support (#142)

* feat: add file browser and file download with multi-backend support

Adds a built-in File Browser page and a File Download system to Hermes
Web UI, enabling users to browse, edit, preview, upload, and download
files from the workspace directly from the web dashboard.

File Browser (/hermes/files):
- New view FilesView.vue plus components under components/hermes/files/
  (FileTree, FileList, FileBreadcrumb, FileToolbar, FileContextMenu,
  FileEditor, FilePreview, FileRenameModal, FileUploadModal)
- New Pinia store stores/hermes/files.ts for directory tree, selection,
  and editing state
- New API module api/hermes/files.ts
- New server routes routes/hermes/files.ts with CRUD, rename, upload,
  and directory listing
- New service services/hermes/file-provider.ts with a pluggable
  provider architecture (local filesystem + multi-terminal backends)

File Download:
- New server route routes/hermes/download.ts and client API
  api/hermes/download.ts
- Integration in chat messages (MessageItem.vue, MarkdownRenderer.vue)
  to surface downloadable file references

Packaging:
- package.json: add a prepare script so the package can be installed
  directly from a git URL with dist/ built automatically

i18n: add files/download translations to en.ts and zh.ts.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* fix: use clipboard fallback for non-secure HTTP contexts

navigator.clipboard is undefined on HTTP intranet deployments (only
available in secure contexts). The previous synchronous calls threw
silently and the success toast still fired, making 'copy' actions
appear broken.

- Add packages/client/src/utils/clipboard.ts with execCommand fallback
  via a hidden textarea
- Use the helper in FileContextMenu (copy file path), CodexLoginModal
  (copy user code), NousLoginModal (copy user code), ChatPanel (copy
  session id)
- Each call now awaits the result and shows success/failure based on
  the actual outcome

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

README_zh.md

@@ -45,6 +45,7 @@
 - Markdown 渲染，支持语法高亮和代码复制
 - 工具调用详情展开（参数 / 结果）
 - 文件上传支持
+- 文件下载支持 — 支持下载用户上传的文件和 Agent 生成的文件，兼容 local、Docker、SSH、Singularity 等多种 terminal backend
 - 全局模型选择器 — 自动从 `~/.hermes/auth.json` 凭证池发现可用模型
 - 每个会话显示模型标签和上下文 Token 用量
 
@@ -236,7 +237,7 @@ npm run build   # 构建输出到 dist/
 
 前端采用 **多 Agent 可扩展架构** — 所有 Hermes 相关代码都按命名空间组织在 `hermes/` 目录下（API、组件、视图、Store），可以方便地并行接入新的 Agent。
 
-BFF 层负责：API 代理（含路径重写）、SSE 流式推送、文件上传、通过 CLI 管理会话 CRUD、配置/凭证管理、微信扫码登录、模型发现、技能/记忆管理、日志读取和静态文件服务。
+BFF 层负责：API 代理（含路径重写）、SSE 流式推送、文件上传与下载（多 Backend 支持：local/Docker/SSH/Singularity）、通过 CLI 管理会话 CRUD、配置/凭证管理、微信扫码登录、模型发现、技能/记忆管理、日志读取和静态文件服务。
 
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