fix: resolve Windows-style backslash paths in input resolution

src/press-resolver.ts

@@ -29,15 +29,16 @@ export interface ResolvedPressCall {
 // ---------------------------------------------------------------------------
 
 /**
- * Determine if a value looks like a resolvable file path (contains `/` and ends with `.md`, excluding URLs).
+ * Determine if a value looks like a resolvable file path (contains a path
+ * separator and ends with `.md`, excluding URLs).
  * @param value - The input string to check.
  * @returns `true` if the value should be read from disk during input resolution.
  */
 export function isResolvablePath(value: string): boolean {
 	if (value.startsWith("http://") || value.startsWith("https://")) {
 		return false;
 	}
-	return value.includes("/") && value.endsWith(".md");
+	return (value.includes("/") || value.includes("\\")) && value.endsWith(".md");
 }
 
 // ---------------------------------------------------------------------------

test/environment.test.ts

@@ -1,4 +1,5 @@
 import { describe, expect, it } from "vitest";
+import { join } from "node:path";
 import { JsEnvironment, SANDBOX_BUILTINS } from "../src/environment.js";
 
 describe("JsEnvironment", () => {
@@ -67,7 +68,7 @@ describe("JsEnvironment", () => {
 	it("require: node built-ins", async () => {
 		const env = new JsEnvironment();
 		const result = await env.exec('const path = require("path"); console.log(path.join("a", "b"))');
-		expect(result.output).toBe("a/b");
+		expect(result.output).toBe(join("a", "b"));
 	});
 
 	it("require: rejects non-builtins", async () => {

test/press-resolver.test.ts

@@ -38,6 +38,10 @@ describe("isResolvablePath", () => {
 		expect(isResolvablePath("/absolute/path/to/file.md")).toBe(true);
 	});
 
+	it("returns true for a Windows-style absolute path", () => {
+		expect(isResolvablePath("C:\\Users\\me\\docs\\file.md")).toBe(true);
+	});
+
 	it("returns false for a bare word like 'haiku'", () => {
 		expect(isResolvablePath("haiku")).toBe(false);
 	});