Add time series line charts to statistics page

- 4 line charts: cumulative repos, commits, stars, lines of code
- SVG-based charts with area fill and data points
- Generator script builds time series from repo creation dates
- Responsive: 2x2 grid on desktop, 1 column on mobile
- Dark themed chart cards matching design system

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: DutchSailor

data/history/2026-04-03.json

@@ -7,7 +7,7 @@
   "totalOpenIssues": 162,
   "totalSizeKB": 11574792,
   "estimatedLinesOfCode": 289369800,
-  "totalCommits": 4173,
+  "totalCommits": 4177,
   "uniqueContributors": 32,
   "languages": 8
 }