Restructure Dashboard Layout (Better Information Hierarchy + Commit Trend)

[bittoby]

Description

Right now the dashboard reads bottom-heavy. You scroll past the leaderboard chart and the entire repo table before you see any summary numbers - the KPI cards are stuck at the very bottom. There's also no sense of direction: everything is a snapshot, nothing shows whether things are going up or down.

We already have a CommitTrendChart component sitting in the codebase unused. It has its own data hook and everything - it just never got wired into the dashboard.

What's wrong

• Summary stats are at the bottom. They should be one of the first things you see, not the last.
• No trend visualization. Static numbers don't tell you if activity is growing, flat, or dropping. Something that shows change over time would be much more useful than big totals.
• Everything is stacked full-width. The repo table and chart could sit side-by-side in some cases, instead of forcing a long vertical scroll.
• "Total Lines Committed" is a questionable headline metric. Less code is often better - a raw line count doesn't really capture quality. Worth rethinking how (or whether) this is featured prominently.

Suggested direction

These are loose guidelines - how you get there is up to you.

• Move summary stats higher so they're visible without scrolling. Think about whether sparklines or mini-trends work better than plain number cards.
• Bring CommitTrendChart onto the dashboard. It already exists at src/components/dashboard/CommitTrendChart.tsx with useHistoricalTrend() - just needs to be imported and placed somewhere sensible.
• Try a denser layout for the lower half (e.g., table + chart side-by-side) instead of everything full-width.

Context

• KPI cards currently render at the bottom of DashboardPage.tsx, after LeaderboardCharts and RepositoriesTable.
• CommitTrendChart and its hook exist but aren't imported anywhere.
• All data already comes from existing endpoints - no backend changes needed.

Reference attachments

[e35ventura]

Tao price and alpha price should not be displayed on UI. They should only ever be used indirectly (eg. calculate $ amounts, reward pool size, etc) and not explicitly shown.