fix: Windows compatibility - USERPROFILE fallback and TCP socket on win32

[NeKoOuO]

Problem

Two bugs prevent walkie-sh from running on Windows:

Bug 1: \process.env.HOME\ is undefined on Windows

Both \src/client.js\ and \src/daemon.js\ used \process.env.HOME\ which is \undefined\ on Windows (the correct variable is \USERPROFILE). Node.js v24 throws \TypeError [ERR_INVALID_ARG_TYPE]\ when \path.join\ receives \undefined.

Bug 2: Unix domain socket not supported on Windows

The daemon uses .sock\ files for IPC, which are Unix-only. On Windows this silently fails with 'Failed to start walkie daemon'.

Fix

• Bug 1: Use \process.env.HOME || process.env.USERPROFILE\ in both files
• Bug 2: On \win32, daemon listens on a random TCP loopback port (\127.0.0.1:PORT) and writes the port number to ~/.walkie/daemon.port. Client reads this file to connect. Unix behavior (domain socket) is unchanged.

Closes #5