- Add DocTypeTree left panel with type grouping (DCSN|GOAL|PLAN|...) and tag grouping
- Add DocWorkspace with three-column layout: tree (260px) | list | detail (~50%)
- Add DocDetailSidebar with read/edit mode toggle, full markdown display
- Add DocDetailHeader with doc-no, title, type, priority, status, evidence links
- Add DocEditor for editing title, type, level, status, tags, body
- Extract doc-no from title prefix (e.g. DCSN-2025-001) and doc-no:* tag
- Support collapsible left/right panels for narrow screens
- Add decision-center-workspace-contract-test.ts for doc-no extraction,
tree grouping, selection, detail display, edit sync
- Add .doc-workspace, .doc-sidebar, .doc-type-tree, .doc-tree-* CSS
Codex