[Remote rendering 4.2] Mode selection and remote entrypoint

### 📝 Description of the feature

Allow VISOR to start in either LOCAL (default) or REMOTE mode.

Backend entrypoint allowing selection of RenderingMode is already in place from 1.3 (wired to a remote stub). This builds the frontend equivalent for the first time.

On mount, the app opens a probe connection to the Trame server, reads which mode it's in and branches: for remote it keeps that connection open and hands it to the remote path rather than reopening one, for local it closes the probe and lets the local path take over. Remote mode must not initialize or download the wasm binary. Both modes serve from the same bundle.

### Acceptance Criteria

Remote mode downloads no wasm binary (no .wasm request in the network tab).
Tests pass

### 💵 Business Value

_No response_

### 🔗 Useful links and references

_No response_

從應用程式掛載點和現有的 RenderingMode 後端進入點開始，接著追蹤 Trame probe 連線、遠端交接和本機 wasm 初始化。執行專案測試並驗證遠端模式會保留 probe 連線，而本機模式會關閉該連線，且遠端模式不會發出 .wasm 請求。

由索引模型根據 Issue 內容生成。