T01: Restructure nav — "Repos" → collapsible "Repository" section with
Repo Sync, SBOM, Debt as sub-pages; Debt moved out of Workstreams
T02: workstream-dod.md migrated from inline const API to config.js import
T03: todo.md suggestion filter (done in previous commit)
Closes CUST-WP-0019. Resolves UI suggestion c2fc284a.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>