- add visitors_by_hour query for hourly breakdown on "today" period
- replace SVG-only chart with HTML/CSS grid layout (bars + labels)
- Y-axis scale with nice rounded max, midpoint, and zero
- X-axis date labels (formatted as "Feb 18") spaced evenly
- adaptive bar gaps (1px for sparse data, 0 for 365-day dense view)
- labels use real HTML text so they're readable on mobile
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>