Why: Removing the artifacts builtin shifts the shortcut ranking, so the
workspaces tests now expect agents at cmd-1; Workbench no longer selects
previewOpen in its outer scope (FilesTab owns that read).
Evidence: npx vitest run 85/85 passed; npm run build (tsc -b && vite
build) passed in the task worktree (SELF).
Impact: test/workspaces.test.ts expectations; Workbench.tsx selector
cleanup. No behavior change beyond the committed layout rework.
Why: The three-column workbench redesign converges entries and hierarchy:
project switching tops the left rail (identity shown once), sessions and
search stay centered, files/workspaces/account sink to the bottom. The
right column becomes a Work/Files third column that absorbs the preview
pane, which is no longer an independent fourth region; the artifacts
workspace overlay folds into the Files entry, and stop control
consolidates into the input area with a light fast/slow-lane status hint.
Evidence: make test-frontend NOT_RUN at commit time; the run and its
outcome are recorded in the Dev task card before integration.
Impact: App.tsx layout and divider width tiers (work 280-560, files with
open preview 420-1100); store UI state rightTab work/files plus filesView
with syncFilesEntry replacing syncPreviewRail; Workbench dual entry;
PreviewPane gains a back-to-list control; TaskSidebar project switcher;
TopBar drops project identity; Conversation drops the header stop button
and gains the input status line; workspaces.ts drops the artifacts builtin.
Refs: three-column workbench proposal (2026-10-11), DESIGN.md 6/9.3
revision follows in the Dev repo.
weichen