dsh-voice-mic: Add voice input for DSH Web GUI

`dsh-voice-mic` is a voice input plugin for DSH Web GUI, designed to streamline the input process for long text or code. It provides a microphone button and an `Alt+V` shortcut key, supporting real-time transcription of recordings written to the input box draft. It does not automatically send messages, ensuring users confirm the content. The plugin supports three recognition engines: first, browser-based recognition using the Web Speech API, suitable for quick testing; second, a local offline backend supporting SenseVoiceSmall and Paraformer models, bound to `127.0.0.1:7860` by default to ensure audio does not leave the local machine, requiring a Python 3.9+ environment; and third, a cloud API compatible with the OpenAI interface, where real-time transcription incurs corresponding fees. Installation requires DSH 0.1.0-