dsh-a11y-announcer: DeepSeek Harness Accessibility Plugin

This plugin aims to address the issue that streamed output from the DeepSeek Harness (DSH) Web UI is not captured by screen readers. It leverages aria-live regions and a debounce mechanism to announce tool calls and final responses in real time after the text stabilizes, while filtering out internal reasoning and duplicate content. Users must manually configure the dependencies and bundle to enable it, making it suitable for accessibility-oriented development scenarios for visually impaired developers on web platforms.