feat: add Windows (PowerShell) daemon support

[nles1214]

Summary

Add Windows 10+ support to wechat-claude-code via a PowerShell daemon manager, enabling the service to run on Windows systems where the bash-based daemon.sh is unavailable.

Changes

• scripts/daemon.ps1 — New PowerShell daemon manager with start, stop, restart, status, logs commands. Uses Start-Process -WindowStyle Hidden -PassThru to run the Node.js daemon in background, PID file tracking, and log output redirection.
• package.json — Added daemon:ps npm script for PowerShell-based daemon control
• README.md / README_zh.md — Updated prerequisites to include Windows 10+, added Windows-specific installation and management instructions
• SKILL.md — Added Windows platform awareness to status checks and subcommand reference

Test Plan

• Service starts successfully on Windows 10 LTSC 2019 (Node.js v24.15.0)
• Status command correctly reports running PID and uptime
• Service stop cleanly terminates the process
• Logs redirect stdout/stderr to ~/.wechat-claude-code/logs/
• WeChat account binding and message bridge functionality verified

Notes

• Windows support uses PowerShell rather than bash/launchd/systemd since those are Unix-only
• The existing daemon.sh for macOS/Linux is unchanged — this is purely additive
• No TypeScript/JS code changes were needed; only platform-specific process management was added