Update documentation from docs/ in main repo
Document the CNV inference tab Add Tab-CNV.md covering controls, workflow, and notes for the new Genes -> CNV tab (InSituCNV/infercnvpy). Link it from the sidebar, Interface Overview, and Home tab-reference table, and add the cnv optional extra (with its insitucnv install-order workaround) to the Installation page's extras table. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01Sk1K3Dt4u923DvpnejNrJV