feat(W-027): Workbench frontend shell — five-region grid + ten empty routes + live StatusFooter (ADR-0160 / ADR-0162) (#299)
- Five-region CSS grid shell (TopBar, LeftNav, Main, StatusFooter; Inspector collapsed)
- Ten placeholder routes with EmptyState cli/string variants and ApiErrorBoundary
- Extended EmptyState API: nextAction accepts string (button) | { kind: "cli", command }
- Updated CommandPalette: real fuzzy search over three commands (Chat, Proposals, Evals)
with ↑/↓/Enter keyboard nav and useInRouterContext degradation for Branch 1 preview
- TanStack Query hooks for all W-026 endpoints; 30s polling on runtime/status
- TypeScript mirror of workbench/schemas.py at src/types/api.ts
- StatusFooter: mutation_mode badge, git_revision (copy on click), checkpoint_revision
with amber warning + ADR-0157/ADR-0158 expansion note
- TopBar: CORE Workbench wordmark, ⌘K palette trigger, connection pill
- ApiErrorBoundary (class component) catches WorkbenchApiError → ErrorState
- scripts/dump-api-schemas.py: AST-based Python dataclass field extractor
- workbench-ui/api-schema-snapshot.json: checked-in drift sentinel
- 51 tests across 10 files (0 failures); enum-coverage 4/4; clean vite build
cdead696ed