dsh-voice-chat-mode: Add an always-on microphone voice chat mode to DSH

BeepFlyer's client-side plugin adds a voice chat mode to DeepSeek Harness (DSH): persistent VAD listening, local SenseVoice transcription, auto-submit, and Edge TTS or system voice broadcasting. It provides the `voice_mode` model tool and broadcast script protocol. It does not self-host ASR/TTS services but reuses DSH's built-in experimental voice bundle, requiring only a single Fetch route and one tool on the Host side. This article introduces core features, installation and activation methods, typical usage, and applicable boundaries, including prerequisites for the built-in voice pack, replacing lines in `cordis.patch.yml`, the `point` uninstall command, as well as precautions such as model-initiated microphone activation, the Edge TTS unofficial API, and running the plugin with DSH process privileges.