feat: improve combination search and offline build

offline/chart-loader.ts

@@ -0,0 +1,24 @@
+import type { ExactSongChart } from '$lib/engine/index.ts';
+
+const chartSources = import.meta.glob('../static/data/charts/*.json', {
+  eager: true,
+  query: '?raw',
+  import: 'default'
+}) as Record<string, string>;
+
+const sourceByFilename = new Map(
+  Object.entries(chartSources).map(([path, source]) => [path.split('/').at(-1) ?? path, source])
+);
+const parsedCharts = new Map<string, ExactSongChart>();
+
+export async function loadExactSongChart(path: string): Promise<ExactSongChart> {
+  const filename = path.split('/').at(-1) ?? path;
+  const cached = parsedCharts.get(filename);
+  if (cached) return cached;
+
+  const source = sourceByFilename.get(filename);
+  if (!source) throw new Error(`포함된 채보 데이터를 찾지 못했습니다: ${filename}`);
+  const chart = JSON.parse(source) as ExactSongChart;
+  parsedCharts.set(filename, chart);
+  return chart;
+}