fix(desktop): open project folders in Windows Explorer on WSL (#1581)

Route Continue in CLI directory opens through wslpath + explorer.exe on
WSL Linux instead of shell.openPath, which often launches Chrome at a
file:// listing via xdg-open.

apps/desktop/src/main/open-project-directory.ts

@@ -0,0 +1,54 @@
+import { execFile, type ExecFileOptionsWithStringEncoding } from "node:child_process";
+import os from "node:os";
+import { promisify } from "node:util";
+
+import { shell } from "electron";
+
+const execFileAsync = promisify(execFile) as (
+  file: string,
+  args: readonly string[],
+  options: ExecFileOptionsWithStringEncoding,
+) => Promise<{ stdout: string; stderr: string }>;
+
+export function isWslLinux(
+  release = os.release(),
+  platform = process.platform,
+): boolean {
+  return platform === "linux" && release.toLowerCase().includes("microsoft");
+}
+
+export type OpenProjectDirectoryDeps = {
+  execFile?: typeof execFileAsync;
+  isWsl?: () => boolean;
+  openPath?: (path: string) => Promise<string>;
+};
+
+/**
+ * Open a validated project directory in the host file manager. On WSL Linux,
+ * `shell.openPath` often delegates to Chrome via xdg-open; route through the
+ * Windows host Explorer instead (issue #1581).
+ */
+export async function openProjectDirectoryInFileManager(
+  resolvedDir: string,
+  deps: OpenProjectDirectoryDeps = {},
+): Promise<string> {
+  const exec = deps.execFile ?? execFileAsync;
+  const openPath = deps.openPath ?? ((path: string) => shell.openPath(path));
+  const isWsl = deps.isWsl ?? (() => isWslLinux());
+
+  if (!isWsl()) {
+    return openPath(resolvedDir);
+  }
+
+  try {
+    const { stdout } = await exec("wslpath", ["-w", resolvedDir], { timeout: 5000 });
+    const winPath = stdout.trim();
+    if (!winPath) {
+      return "wslpath returned an empty Windows path";
+    }
+    await exec("explorer.exe", [winPath], { timeout: 5000 });
+    return "";
+  } catch (err) {
+    return err instanceof Error ? err.message : String(err);
+  }
+}

apps/desktop/src/main/runtime.ts

@@ -16,6 +16,7 @@ import {
 import type { OpenDesignHostActionResult, OpenDesignHostUpdaterActionOptions } from "@open-design/host";
 
 import { createElectronPdfTarget, exportPdfFromHtml, savePrintReadyDocumentAsPdf } from "./pdf-export.js";
+import { openProjectDirectoryInFileManager } from "./open-project-directory.js";
 import type { PrintReadyPdfOptions } from "./pdf-export.js";
 import type { DesktopUpdater } from "./updater.js";
 
@@ -1198,7 +1199,7 @@ export async function createDesktopRuntime(options: DesktopRuntimeOptions): Prom
     const validated = await validateExistingDirectory(resolved.context.resolvedDir);
     if (!validated.ok) return `open-path: ${validated.reason}`;
     try {
-      return await shell.openPath(validated.resolved);
+      return await openProjectDirectoryInFileManager(validated.resolved);
     } catch (err) {
       return err instanceof Error ? err.message : String(err);
     }

apps/desktop/tests/main/open-project-directory.test.ts

@@ -0,0 +1,62 @@
+import { describe, expect, it, vi } from "vitest";
+
+import {
+  isWslLinux,
+  openProjectDirectoryInFileManager,
+} from "../../src/main/open-project-directory.js";
+
+describe("isWslLinux", () => {
+  it("detects WSL kernels via microsoft in the release string", () => {
+    expect(isWslLinux("5.15.133.1-microsoft-standard-WSL2", "linux")).toBe(true);
+    expect(isWslLinux("6.8.0-45-generic", "linux")).toBe(false);
+    expect(isWslLinux("5.15.133.1-microsoft-standard-WSL2", "darwin")).toBe(false);
+  });
+});
+
+describe("openProjectDirectoryInFileManager", () => {
+  it("uses shell.openPath on native Linux", async () => {
+    const openPath = vi.fn(async () => "");
+    const execFile = vi.fn();
+
+    const result = await openProjectDirectoryInFileManager("/tmp/project", {
+      isWsl: () => false,
+      openPath,
+      execFile,
+    });
+
+    expect(result).toBe("");
+    expect(openPath).toHaveBeenCalledWith("/tmp/project");
+    expect(execFile).not.toHaveBeenCalled();
+  });
+
+  it("routes through wslpath and explorer.exe on WSL (#1581)", async () => {
+    const execFile = vi.fn(async (cmd: string, args: readonly string[]) => {
+      if (cmd === "wslpath") {
+        return { stdout: "C:\\Users\\me\\project\r\n", stderr: "" };
+      }
+      return { stdout: "", stderr: "" };
+    });
+    const openPath = vi.fn();
+
+    const result = await openProjectDirectoryInFileManager("/home/me/project", {
+      isWsl: () => true,
+      execFile,
+      openPath,
+    });
+
+    expect(result).toBe("");
+    expect(execFile).toHaveBeenNthCalledWith(
+      1,
+      "wslpath",
+      ["-w", "/home/me/project"],
+      { timeout: 5000 },
+    );
+    expect(execFile).toHaveBeenNthCalledWith(
+      2,
+      "explorer.exe",
+      ["C:\\Users\\me\\project"],
+      { timeout: 5000 },
+    );
+    expect(openPath).not.toHaveBeenCalled();
+  });
+});