feat(profile): contributor stats dashboard (#836)

[aunysillyme]

/claim #836

⚠️ This PR is AI-assisted. It was implemented end-to-end by Claude (Anthropic) at the request of the bounty hunter. Please review the diff carefully before merging.

Summary

Builds the Contributor Profile Stats Dashboard described in #836. The profile page now leads with a stats dashboard — visible before the existing tabbed area — that pulls together GitHub activity, FNDRY/USDC earnings history, and headline contributor metrics.

What landed

• GitHub activity heatmap (GitHubActivityGraph) — last 90 days of public events from api.github.com/users/{username}/events/public, rendered as a GitHub-style daily heatmap (SVG, no extra deps) with a per-event-type breakdown (commits, PRs, issues, reviews).
• Earnings history chart (EarningsHistoryChart) — stacked monthly bar chart of USDC + FNDRY payouts (recharts), with a 6mo / 12mo range toggle, built from the contributor's approved submissions joined against their bounty rewards.
• Key stats row (StatsRow) — total earned (USDC + FNDRY), bounties completed, current / longest contribution streak (derived from the GitHub event stream), and rolling event count.
• /api/users/me/submissions client + useMySubmissions hook — graceful 404/501 fallback so the panel renders an empty-but-useful state until the backend ships that endpoint.

Drive-by fix

The repo-wide .gitignore had a lib/ rule (intended for Python venvs) that was silently catching frontend/src/lib/. The lib/utils and lib/animations modules were referenced across ~20 frontend files but had never been committed — tsc and vite build both failed on main before this PR. The ignore is narrowed to venv paths and the two missing modules are now tracked.

Files

• frontend/src/api/github.ts + hooks/useGitHubActivity.ts — GitHub events fetcher with weight-by-commit-count and streak math
• frontend/src/components/profile/{ContributorStatsPanel,GitHubActivityGraph,EarningsHistoryChart,StatsRow}.tsx
• frontend/src/api/bounties.ts + hooks/useBounties.ts — new listMySubmissions / useMySubmissions with 404 fallback
• frontend/src/components/profile/ProfileDashboard.tsx — wires the new panel into the existing dashboard
• frontend/src/lib/{utils,animations}.ts — restored shared helpers (formatCurrency / timeAgo / animation variants)
• frontend/src/__tests__/{github-activity,utils}.test.ts — 12 new passing unit tests covering event aggregation, streak computation, and number/date formatting
• .gitignore — narrow the Python lib/ ignore so it doesn't swallow the frontend lib folder

Test plan

• npx tsc --noEmit — clean
• npx vite build — succeeds (previously failed on main because of the missing lib/ modules)
• npx vitest run src/__tests__/github-activity.test.ts src/__tests__/utils.test.ts — 12/12 pass
• Dev server (npx vite) boots and serves the profile page without runtime errors
• Manual smoke test against a real GitHub account (recommend reviewer try their own username — the heatmap is hydrated client-side from the public events API, no token required)

Acceptance criteria mapping

• ✅ GitHub activity graph (commits, PRs, issues) via GitHub API → GitHubActivityGraph + api/github.ts
• ✅ Earning history chart showing FNDRY payouts over time → EarningsHistoryChart (stacked USDC + FNDRY)
• ✅ Key stats: total earned, bounties completed, contribution streak → StatsRow

Notes for reviewers

• The GitHub public events feed only returns ~90 days of data and is unauthenticated, so it has a 60 req/hr per-IP rate limit. The query is cached in React Query for 5 minutes per username, so the typical session stays well under that.
• Earnings rely on /api/users/me/submissions returning approved submissions. The frontend handles a missing endpoint gracefully (empty state); the panel will light up automatically once the backend exposes it.

🤖 Generated with Claude Code