feat(dashboard): add reusable empty state components for widgets

[desireddymohithreddy0925]

Summary

Replaces ad-hoc blank state messages across various dashboard widgets with the unified EmptyState component for a more consistent, informative, and engaging user experience.

Closes #2646

Type of Change

• 🐛 Bug fix (non-breaking change that fixes an issue)
• ✨ New feature (non-breaking change that adds functionality)
• 💥 Breaking change (fix or feature that changes existing functionality)
• 📝 Documentation update
• 🎨 Code style update (formatting, renaming)
• ♻️ Refactoring (no functional changes)
• 🧪 Testing
• 🏗️ Build / CI/CD / Infrastructure

Description

Several dashboard widgets previously displayed blank sections or minimal placeholder text when no data was available. This update standardizes these edge cases using the reusable EmptyState component.

Changes made:

• EmptyState.tsx: Added an onAction prop to support action buttons alongside the existing actionHref link support.
• TopRepos.tsx (Repositories Widget): Implemented EmptyState for when a user has no pinned or top repositories found.
• PRReviewTrendChart.tsx (PR Analytics Widget): Replaced the standard border box empty state with EmptyState and an action to view their GitHub profile.
• RecentActivity.tsx (Activity Widget): Updated to use EmptyState with a direct onAction button that refreshes the activity feed.
• Note: The Goals Tracker and Leaderboard widgets were already using EmptyState effectively.

Testing

• Tested rendering widgets on an account with zero data.
• Verified actionHref links point correctly.
• Verified onAction correctly fires reload functions on empty states.
• Executed local static analysis (pnpm typecheck) seamlessly without type errors.

[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]

The idea here is in scope and worth having — DevTrack does want consistent empty states, and the docs really should say pnpm rather than npm. The problem is the branch, not the intent.

This branch is stacked on your task-management work, so it carries all of that too: /api/tasks, the kanban and recurrence migrations, and the scratch_*.py working files. That's why a change described in one line shows 31–35 changed files. I've closed the task-management PRs as out of scope (DevTrack is a GitHub-activity analytics dashboard, not a project tracker), which leaves this one carrying code that isn't going to land.

To move it forward:

git checkout main && git pull
git checkout -b feat/empty-states-clean
# re-apply only the EmptyState work

A PR touching src/components/EmptyState.tsx plus the widgets that use it — and nothing else — I'd review the same day. Same for the npm→pnpm docs pass on its own branch; that one is genuinely useful and would go straight in.

Leaving this open so you can force-push a clean branch to it if you'd rather not open a new one.