feat: dashboard widget drag-drop customization with persistence

[DHEVIKA]

Features

• Drag & drop dashboard widgets using dnd-kit
• Persistent widget order using localStorage
• Backend sync for user-specific layout
• Hide/show widgets in edit mode
• Reset layout option
• Keyboard + mobile support

Implementation

• @dnd-kit/core + sortable
• Next.js API route for layout storage
• localStorage + DB hybrid persistence
• NextAuth session-based user identification

Notes

Backend uses in-memory storage for demo purposes (can be upgraded to DB later).

[vercel]

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[github-actions]

GSSoC Label Checklist 🏷️

@Priyanshu-byte-coder — please apply the appropriate labels before merging:

Difficulty (pick one):

• level:beginner — 20 pts
• level:intermediate — 35 pts
• level:advanced — 55 pts
• level:critical — 80 pts

Quality (optional):

• quality:clean — ×1.2 multiplier
• quality:exceptional — ×1.5 multiplier

Validation (required to score):

• gssoc:approved — counts for points
• gssoc:invalid / gssoc:spam / gssoc:ai-slop — does not score

Type labels (type:*) are auto-detected from files and title. Review and adjust if needed.
Points formula: (difficulty × quality_multiplier) + type_bonus

[Priyanshu-byte-coder]

Thanks @DHEVIKA for the dashboard drag-drop widget! The concept is great and the implementation with @dnd-kit looks promising. However, there are two issues blocking the merge:

Build failure + Blockers:

1. pnpm-lock.yaml and pnpm-workspace.yaml — This project uses npm, not pnpm. These files should not be added and are likely causing the build failure. Please delete them and ensure you run npm install (not pnpm install).
2. next.config.mjs — Please check what changes you made here. Ensure output: 'standalone' is preserved.
3. Rebase needed — DashboardHeader.tsx has been modified by recent merges. Please rebase onto main.

Once you fix the pnpm files and rebase, please verify the build passes locally with npm run build. The drag-drop persistence feature is a valuable addition!

[Priyanshu-byte-coder]

Two issues:

1. pnpm files: This PR includes pnpm-workspace.yaml and pnpm-lock.yaml. This project uses npm, not pnpm. Please remove these files.
2. Merge conflicts: There are conflicts with current main in multiple files. Please rebase after removing the pnpm files.

[Priyanshu-byte-coder]

Your PR has conflicts with the current main branch. Please rebase on main to resolve conflicts and this can be reviewed for merging. Labels have been added ✅