Create CONTRIBUTING.md

I just added this since i see most people are confused and this should tell them before starting any issues...

CONTRIBUTING.md

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+# Contributing to MikuMikuBeam!
+
+Welcome! before you start makeing **ANY** issues. (or requests) ***Did you***?
+
+- Have carefully **READ** the entirely [Setup](https://github.com/sammwyy/MikuMikuBeam?tab=readme-ov-file#setup-%EF%B8%8F) and [Installation](https://github.com/sammwyy/MikuMikuBeam?tab=readme-ov-file#installation-)?
+- open the terminal or command prompt in your Miku folder? (psst, clone or download the repo first and then enter it)
+- Have Node.js (v14 or above) and npm installed onto your pc (or server?) first?
+- run `git pull` # to be in the latest version.
+- Make `proxies.txt` amd `uas.txt` if it doesn't exist in the data folder. (if it does exist then ignore this part.)
+- run `npm install` in the terminal (im assuming you are useing ubuntu, or windows terminal....)
+- and then run `npm run dev` to start the server!
+- then go to [localhost:5173](http://localhost:5173/)
+and it should look like this! (Im useing Dark reader but you will see the same thing. The "active bots" number will be diffrent for each user)
+![Dark mode](https://github.com/user-attachments/assets/7407c4b8-7952-4b26-ae2d-6772a537f466)
+Last of all, please check for existing issues before reporting any issues.
+
+
+### 🐛 Reporting Issues
+If you find a bug or have a feature request, please open an [issue](https://github.com/sammwyy/MikuMikuBeam/issues) and include:
+- A clear and descriptive title.
+- Steps to reproduce (if applicable).
+- Expected vs. actual behavior.
+- Relevant screenshots or logs.
+
+### 🔧 Submitting a Pull Request (PR)
+1. **Fork the repository** and create a new branch:
+   ```sh
+   git checkout -b feature/your-feature