Scaffold Chart Sins site with Astro + build-time Vega-Lite

Set up the static-site tech stack: Astro 5 with Markdown content
collections, Vega-Lite specs rendered to static SVG at build time
(zero client JS), plain scoped CSS, and a GitHub Pages deploy workflow.

Includes three sample sins (truncated y-axis, dual-axis deception,
pie chart overload), each with a bad and fixed chart spec, plus a
gallery index and per-sin detail pages.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XPEvmMbac2fCvKXpQcovj8

src/content/sins/pie-chart-overload.md

@@ -0,0 +1,31 @@
+---
+title: "Pie Chart Overload"
+summary: "Eight near-identical slices no human eye can rank. A bar chart was right there."
+category: "Chart-Type Abuse"
+severity: 3
+tags: ["pie chart", "part-to-whole", "comparison"]
+badChart: "pie-overload-bad"
+fixedChart: "pie-overload-fixed"
+date: 2026-08-05
+---
+
+## The sin
+
+The pie chart asks the reader to compare **angles** — something people are
+genuinely bad at. One or two slices, fine. But eight slices, several of them
+within a percentage point of each other? Nobody can tell whether Firefox beats
+Samsung by eyeballing two thin wedges on opposite sides of the circle.
+
+## Why it deceives
+
+Angle and area are hard to judge precisely, and slices scattered around the
+circle can't be lined up against a common baseline. The small categories blur
+into an indistinguishable fringe, and the ranking — usually the whole point —
+becomes guesswork.
+
+## The repentance
+
+Use a **sorted horizontal bar chart**. Every value shares one baseline, the
+ordering is explicit, and long labels sit comfortably beside their bars. Reserve
+the pie for the rare case of two or three parts of an obvious whole — and even
+then, a bar chart rarely does worse.