chore(vendor): import pi 0.85.1

Imported as a linear vendor commit so forge rebases do not replay the upstream root tree.

git-subtree-dir: third_party/pi

git-subtree-split: d981de1229ef899957bbe968bc8dcda02a21f477

third_party/pi/packages/coding-agent/src/utils/highlight-js.d.ts

@@ -0,0 +1,36 @@
+interface HighlightJsResult {
+	value: string;
+}
+
+interface HighlightJsOptions {
+	language: string;
+	ignoreIllegals?: boolean;
+}
+
+interface HighlightJsLanguageDefinition {
+	readonly name?: string;
+}
+
+type HighlightJsLanguageFactory = (hljs: HighlightJsApi) => HighlightJsLanguageDefinition;
+
+interface HighlightJsApi {
+	highlight(code: string, options: HighlightJsOptions): HighlightJsResult;
+	highlightAuto(code: string, languageSubset?: string[]): HighlightJsResult;
+	getLanguage(name: string): HighlightJsLanguageDefinition | undefined;
+	registerLanguage(name: string, language: HighlightJsLanguageFactory): void;
+}
+
+declare module "highlight.js/lib/core.js" {
+	const hljs: HighlightJsApi;
+	export default hljs;
+}
+
+declare module "highlight.js/lib/index.js" {
+	const hljs: HighlightJsApi;
+	export default hljs;
+}
+
+declare module "highlight.js/lib/languages/*.js" {
+	const language: HighlightJsLanguageFactory;
+	export default language;
+}