dsh-record: Add a recording button to the DSH input box, attach the recording directly to the prompt after recording.

dsh-record is a DeepSeek Harness client plugin maintained by most-silence and licensed under the MIT protocol. It registers a microphone button in the `conversation.input.right` slot of the composer; clicking once starts recording, and clicking again stops it. The recording is attached to the current prompt and sent via the normal upload queue. Output formats (MP3, WAV, or WebM) are selected in the plugin settings: MP3 uses `lamejs` for browser-side encoding at 128 kbps CBR; WAV uses 16-bit PCM lossless re-packaging; and WebM uses the browser's native Opus container without transcoding, falling back to the original WebM if transcoding fails. The plugin is solely responsible for recording, transcoding, and mounting; it does not write to disk or perform speech recognition, requiring an external speech-to-text plugin. The installation method involves a local build followed by `dsh plugin --profile <profile> add file:$PWD`. The README documents two critical hardening rules: `lamejs` must be bundled inline, and the Config schema must use `z.union` instead of `z.enum`. The README was verified with the dsh version 0.2.1-rc.2.