Xan 0.9.0 adds terminal data visualization

Xan 0.9.0 ships a markdown-style cookbook that lets engineers plot data without leaving the shell [GitHub Docs]. The new dataviz.md file documents helper functions—xan.line(), xan.bar(), and xan.scatter()—that emit Unicode block characters wrapped in ANSI colour codes. For example, rendering a CSV of 10 000 points takes 150 ms on a 2024 MacBook Pro M2 Max. The cookbook includes three concrete use-cases: xan line data.csv --term for line charts, xan bar metrics.json --term --color=green for bar charts, and xan scatter points.tsv --term --size=2 for scatter plots [Lobsters]. All examples run on Linux, macOS, and WSL2 without additional dependencies, relying only on the standard curses library. The cookbook's approach reduces context-switching, enables reproducible reporting, and lowers the barrier for remote debugging. By codifying charts in markdown, Xan treats visualizations as first-class artifacts in the same repository as the code they describe, forcing teams to think about observability like test coverage.