Refresh the README and use a local logo

- Reference logo.png from the repo instead of the dead raw.github URL
  (the logo lives in the common submodule, which Gitea can't serve from
  a relative path, so a copy sits next to screenshot.png)
- Drop the section emojis and horizontal-rule separators
- Add supported versions, the built-in mods, installation (Modrinth,
  releases), network use (Mojang session sign-in; the access token never
  reaches the Saturn server), building from source with submodules, and
  a pointer to the version guide for multi-version changes

Co-Authored-By: Claude Opus 5.5 <[email protected]>

README.MD

@@ -1,5 +1,5 @@
 <p align="center">
-  <img src="https://raw.github.com/saturnclientmc/common/master/src/main/resources/assets/saturnclient/textures/logo/logo.png" alt="Saturn Client Logo" width="150px"/>
+  <img src="logo.png" alt="Saturn Client Logo" width="150px"/>
 </p>
 
 <h1 align="center">Saturn Client</h1>
@@ -13,27 +13,47 @@
   <img src="screenshot.png" alt="Saturn Client Screenshot"/>
 </p>
 
----
+## About
-
-## ✨ About
 
 Saturn Client is a free, open-source Minecraft client designed to enhance the gameplay experience while staying lightweight and customizable.
 Our goal is to build a clean, optimized client that the community can contribute to and improve together.
 
-Saturn is currently trying to support multiple versions of minecraft, so please report any issues you are experiencing.
+Saturn runs on Fabric and supports **Minecraft 1.21.4 to 1.21.11**, with one build per version. If something doesn't work on your version, please open an issue.
 
----
+## Features
 
-## 🚀 Features
+- Free cosmetics that don't require real money: cloaks, including animated ones, and hats
-
+- 18 built-in mods: Armor Display, Auto Sprint, Clock, Coordinates, Crosshair, Day Counter, FPS Display, Freelook, Fullbright, Health Display, Keystrokes, Nametags, No Fog, Ping Display, Speedometer, Status Effects, TPS Display and Zoom
-- Free cosmetics that don't require real money
 - Clean and modern UI with animations
 - Ongoing performance improvements
 - Open-source and community-driven
 
----
+## Installation
 
-## 🤝 Contributing
+1. Install [Fabric Loader](https://fabricmc.net/use/) and [Fabric API](https://modrinth.com/mod/fabric-api) for your Minecraft version.
+2. Download the Saturn Client jar for the same version from [Modrinth](https://modrinth.com/mod/saturnclient) or the [releases page](https://git.selimaj.dev/saturnclientmc/saturnclient/releases).
+3. Put it in your `mods` folder.
+
+### Network use
+
+For cosmetics, Saturn Client connects to the Saturn server (`saturn-server.selimaj.dev`). You're signed in the same way as on an online-mode Minecraft server: your client proves who you are to Mojang's session server, and the Saturn server asks Mojang to confirm it. **Your Minecraft access token is only ever sent to Mojang, never to the Saturn server.**
+
+## Building from source
+
+The version-independent code lives in the `common` submodule, so clone with submodules:
+
+```sh
+git clone --recurse-submodules https://git.selimaj.dev/saturnclientmc/saturnclient.git
+cd saturnclient
+
+./gradlew buildAll                    # every version → build/allJars/
+./gradlew :mc-1.21.11:build           # a single version
+./gradlew :mc-1.21.11:runClient       # launch a development client
+```
+
+Building needs Java 21.
+
+## Contributing
 
 We welcome contributions of all kinds:
 
@@ -43,27 +63,23 @@ We welcome contributions of all kinds:
 - Cosmetic designs
 - Suggestions and feedback
 
-If you're an artist or designer interested in helping with cosmetics or visual assets, we’d love to collaborate.
+If you're an artist or designer interested in helping with cosmetics or visual assets, we'd love to collaborate.
 
----
+Most features belong in `common`, which every Minecraft version shares. For code that differs between versions, see the [version guide](VERSION_GUIDE.md): it covers how the versions are laid out, porting a change to all of them with `scripts/port.sh`, and adding a new Minecraft version. Every pull request is compiled for all versions automatically.
 
-## 🙌 Credits
+## Credits
 
 - **Cloak Rendering:** `IIpho3nix` & Saturn
 - **Who Am I:** `FokshaWasTaken`
-- **Panorama:**  
+- **Panorama:**
   https://www.planetminecraft.com/texture-pack/minecraft-cavesand-cliffs-part-ii-main-menu-panorama/
 
-If any code or assets belong to you and you would like them removed, please open an issue.  
+If any code or assets belong to you and you would like them removed, please open an issue.
 We aim to properly credit all contributors and respect original creators of their respective art.
 
----
+## License
 
-## 📜 License
+Saturn Client is free and open-source under the **Apache-2.0** license.
-
-Saturn Client is free and open-source using **Apache-2.0**
-
----
 
 <p align="center">
   Made with ❤️ by the Saturn Client team