chore: add design tokens\css lint rules

web/eslint-plugins/design-tokens/style-context.js

@@ -0,0 +1,19 @@
+// Shared helpers to talk to the postcss AST of Svelte <style> blocks that
+// svelte-eslint-parser exposes. All rules use the same plumbing.
+
+// Returns the postcss Root of the <style> block, or null when the file is not
+// a Svelte component (or its style failed to parse).
+export function getStyleRoot(context) {
+	const parserServices = context.sourceCode?.parserServices;
+	if (!parserServices || typeof parserServices.getStyleContext !== "function") {
+		return null;
+	}
+	const styleContext = parserServices.getStyleContext();
+	return styleContext?.status === "success" ? styleContext.sourceAst : null;
+}
+
+// Returns a converter from a postcss node to an ESLint loc, or null if the
+// parser doesn't expose it.
+export function getStyleNodeLoc(context) {
+	return context.sourceCode?.parserServices?.styleNodeLoc ?? null;
+}