fix: resolve spawn EINVAL on Windows for .cmd Pi binary

[alexliu072903-bit]

Problem

On Windows, child_process.spawn() cannot directly execute .cmd files without shell: true. When the Pi binary path points to pi.cmd (the standard npm global install on Windows), the plugin throws:

Error: spawn EINVAL

This makes the plugin completely non-functional on Windows out of the box.

Fix

Add shell: process.platform === "win32" to the spawn options in src/rpc.ts:

this.process = spawn(this.piBinaryPath, ["--mode", "rpc", ...this.extraArgs], {
    cwd: this.cwd,
    stdio: ["pipe", "pipe", "pipe"],
    env: { ...process.env },
    shell: process.platform === "win32",
});

This is platform-gated so it only applies on Windows and has no effect on macOS/Linux.

Tested on

• Windows 11, Node.js 20, Pi binary at C:\Users\<user>\AppData\Roaming\npm\pi.cmd
• Plugin now connects successfully and streams responses from Pi

Related

Discovered while building obsidian-ai-starter, a setup guide for Pi + Obsidian on Windows.