- Merge titlebar and tab bar into a single unified top bar (.titlebar)
- Remove redundant floating workspace button that caused overlap on collapsed sidebar
- Ensure tab bar left aligns with terminal window when workspace sidebar is expanded
- Allow tab bar to sit naturally at leftmost position when workspace sidebar is collapsed
- Update test runner suite to cover merged titlebar and alignment behavior
- Restructure UI layout: tab bar and stage actions are now housed inside .workspace-stage (.workspace-header), aligning 100% with the terminal window (#main-viewport) below it
- Establish clear workspace hierarchy: Global Titlebar -> Left Workspace Sidebar -> Active Workspace Content Stage (Tab Bar + Terminal Viewport)
- Add active workspace indicator badge to titlebar header
- Introduce comprehensive automated test suite (test/test-runner.cjs) covering PTY process lifecycle, workspace hierarchy, stage alignment, tab creation, split panes, shortcuts, and themes
- Add 'npm test' script to package.json