dsh-idea: A DeepSeek Harness Plugin for Discovering External Opportunities

`dsh-idea` is a critical plugin within the DeepSeek Harness (DSH) ecosystem, focused on transforming external market signals into actionable product opportunities. Through public page scanning, filtering and ranking, and opportunity construction workflows, it helps developers identify real demand. This plugin belongs to the “demand stage” layer and collaborates with `dsh-business` and `dsh-product` to ensure that opportunities are validated and converted into versioned handoff contracts, rather than direct product requirements. Maintainers should note the need to install it into the designated profile and address build-blocking issues.