dsh-gap-feed: Conversation Stream Injection Plugin for Extended Thinking

The `dsh-gap-feed` plugin is designed to address the lack of user awareness caused by the silence of DeepSeek Harness (DSH) agents during extended thinking periods. It supports fetching news from Toutiao, GitHub Trending, and the Bilibili trending list, and allows users to set reminders using natural language. The plugin features a smart triggering mechanism that injects cards only when an agent has been thinking for a long time and after a cooldown period has elapsed, avoiding disruptions to the conversation. It also provides a visual configuration page for managing reminders, supports deduplication and priority sorting, and offers data persistence to ensure data remains available after restarts.