feat: Add QWeather (和风天气) API support for China users

[ThendCN]

Summary

Weather Underground has limited coverage in China, making it difficult for Chinese users to find local weather stations. This PR adds support for QWeather (和风天气), a popular weather data provider in China with excellent coverage of Chinese cities.

Changes

New Files

• plasmoid/contents/code/qweather-api.js - Full QWeather API implementation

Modified Files

• plasmoid/contents/ui/main.qml - Switch to QWeather API
• plasmoid/contents/ui/config/ConfigStation.qml - Add API Key configuration UI
• plasmoid/contents/ui/lib/StationSearcher.qml - Use QWeather for city search
• plasmoid/contents/ui/lib/StationMapSearcher.qml - Use QWeather for map search
• plasmoid/contents/config/main.xml - Add qweatherApiKey config entry

Features

• City Search: Search Chinese cities by name (中文) or pinyin
• Current Weather: Real-time weather data with temperature, humidity, wind, pressure
• 7-Day Forecast: Daily weather forecast
• Hourly Forecast: 24-hour weather forecast
• Air Quality: AQI data for Chinese cities
• Weather Alerts: Official weather warnings

Configuration

Users need to:

1. Register at https://console.qweather.com/
2. Create a project and get API Key
3. Enter API Key in widget settings
4. Search for cities using Chinese names or pinyin

Technical Details

• Uses X-QW-Api-Key header for authentication
• Normalizes language codes (zh-CN → zh) for QWeather compatibility
• Maps QWeather icon codes to existing widget icons

Screenshots

(Weather data for 黄岛/Huangdao, which was not available on Weather Underground)

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This is my first contribution. Happy to make any changes if needed!

[k-donn]

Wow! This is amazing. Thank you for doing this!

I am always looking for ways to improve this widget for more people. Despite that, I have to manage my time to support this widget. I have built it around Wunderground and want to keep it that way as long as I can. Supporting the infrastructure around two sources would go in a direction I do not want to go. I am probably not going to merge these changes into the main branch.

However! I would love to distribute these changes as an additional option on the KDE Store. You are also more than welcome to distribute it yourself as this is a GPL-2.0 project. If there are any distribution options that would meet a Chinese audience better, feel free to distribute it there too!

Going forward, you are welcome to incorporate further changes I make into the widget. You can even keep this pr open and keep the branch in sync if you want. When I push out changes, you can merge/rebase this fork. Feel free to reach out if there is a conflict, and I would love to help to clear it.

Thanks again for your interest and I want you to know how much your interest means to me! If you are okay with me distributing the fork, let me know.

Have a good day!