feat: redesign workspace card header and layout

- Swap workspace card header order: project name is now the primary eyebrow,
  workspace name is the bold title below it.
- Restructure workspace card into clean top/body/actions sections with more
  whitespace and clearer hierarchy.
- Replace cramped meta paragraphs with an inline meta row (repo, branch,
  instance count) and dedicated instance chip area.
- Use icon-only ghost buttons for sync/delete to reduce visual noise; keep
  prominent Start Tool button.
- Add top divider for actions, improve hover states, and make long names
  truncate gracefully.
- Update mobile workspace list subtitle to project · workspace name.
- Refresh workspaces.css with new card layout and responsive mobile rules.

Quality gates: npm run typecheck clean, npm run lint clean,
npm test -- --run 87 passed

apps/web/src/pages/WorkspacesPage.tsx

@@ -104,7 +104,7 @@ export function WorkspacesPage() {
 						items={workspaces.map((ws) => ({
 							id: ws.id,
 							title: ws.name,
-							subtitle: `${ws.project_name} · ${ws.repo_name} · ${ws.branch}`,
+							subtitle: `${ws.project_name} · ${ws.name}`,
 							status: ws.status,
 						}))}
 						onItemClick={(id) => {