[Dashboard Modularization] Admin configuration UI: add/remove/reorder/resize widgets.

[armoredvortex]

Implement the admin-only dashboard configuration UI described in the GSoC project plan (Deliverable 4).
Superusers will be able to customise the dashboard layout interactively.

Plan

• src/stores/useDashboardStore.js : Zustand store (persisted to localStorage) holding widgetConfigs, layouts, isDirty, and savedVersion. All dashboard layout state now lives here instead of being hardcoded in defaultDashboardConfig.js.
• src/components/dashboard/ConfigEditor.jsx : Admin editor accessible at /dashboard/config.
• Dashboard.jsx — Reads widgetConfigs/layouts from the store; shows a Configure button for superusers.
• Routes.jsx — Adds /dashboard/config to authRoutesLazy, wrapped in AuthGuard + SuperuserGuard.
• AppHeader.jsx — Adds a Config nav item visible only when isSuperuser is true.
• stores/index.js — Exports useDashboardStore.

Acceptance criteria

• Admin can add a widget from the available panel
• Admin can remove a widget via the X button
• Admin can drag widgets to reorder
• Admin can resize widgets using the corner handle
• Reset restores the default layout

[piyushzgautam99-ship-it]

Hi @regulartim , I'd like to work on this issue. I have experience with React and frontend development, and I'd love to contribute. Could you please assign this issue to me? Thanks!

[armoredvortex]

Hi @piyushzgautam99-ship-it , this is part of Google summer of Code project. Im already actively working on this issue :)