Dark mode as default theme with light/dark toggle

[PlayerNguyen]

Problem statement

The app currently defaults to light mode with no dark mode support. Users expect a dark-themed dashboard experience.

Proposed solution

• Set defaultColorScheme="dark" on MantineProvider in App.tsx
• Add a Theme toggle (Dark/Light) in the sidebar footer dropdown (post-Configurable sidebar items via configureSidebar.tsx #15/Sidebar footer with cogwell and dropdown menu #18)
• Persist choice in localStorage

Dependencies

• Configurable sidebar items via configureSidebar.tsx #15 — Configurable sidebar items
• Sidebar footer with cogwell and dropdown menu #18 — Sidebar footer with cogwell and dropdown menu

Reference plan

.opencode/plans/08-07-2026/17-33_dark-mode-theme-toggle.md

Area

UI (apps/ui/)

Priority

Important