chore(root): migrate build scripts and plugins to TypeScript (#1052)

build/plugins/inline-css-plugin.ts

@@ -0,0 +1,61 @@
+import { readFileSync } from 'node:fs';
+import { dirname, relative, resolve } from 'node:path';
+import { transform } from 'lightningcss';
+import { resolveImports } from './resolve-css-imports.ts';
+import type { BuildPlugin } from './types.ts';
+
+const INLINE_PREFIX = 'inline-css:';
+
+const INLINE_SUFFIX = '?inline';
+
+interface InlineCssPluginOptions {
+  skinsDir: string;
+  rootDir?: string;
+  minify?: boolean;
+}
+
+/**
+ * Rolldown/tsdown plugin that inlines `.css?inline` imports as JavaScript
+ * modules exporting the resolved CSS string. Mirrors the Vite `?inline`
+ * convention so the same source works in both Vite dev and tsdown builds.
+ */
+export function inlineCssPlugin(options: InlineCssPluginOptions): BuildPlugin {
+  const { skinsDir, rootDir = process.cwd(), minify = true } = options;
+
+  return {
+    name: 'inline-css',
+
+    resolveId(source, importer) {
+      if (!source.endsWith(INLINE_SUFFIX)) return null;
+
+      const cssPath = source.slice(0, -INLINE_SUFFIX.length);
+      const abs = resolve(dirname(importer!), cssPath);
+      const rel = relative(rootDir, abs);
+
+      // Use .js extension so rolldown doesn't apply its CSS loader.
+      return { id: `${INLINE_PREFIX}${rel.replace(/\.css$/, '.js')}`, moduleSideEffects: false };
+    },
+
+    load(id) {
+      if (!id.startsWith(INLINE_PREFIX)) return null;
+
+      // Map back to the .css file path.
+      const rel = id.slice(INLINE_PREFIX.length).replace(/\.js$/, '.css');
+      const file = resolve(rootDir, rel);
+      const raw = readFileSync(file, 'utf-8');
+      let resolved = resolveImports(raw, dirname(file), skinsDir);
+
+      if (minify) {
+        const { code } = transform({
+          filename: file,
+          code: Buffer.from(resolved),
+          minify: true,
+        });
+
+        resolved = code.toString();
+      }
+
+      return { code: `export default ${JSON.stringify(resolved)};`, moduleSideEffects: false };
+    },
+  };
+}