Add MIT license

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

README.md

@@ -72,3 +72,9 @@ Use *Save Game* in the pause menu to download a `.dcsave` file (JSON). Load it a
 1. Copy `lang/en.lang` to `lang/<code>.lang` and translate the texts (placeholders `{0}`, `{1}` stay as they are).
 2. Add the file to `SOURCES` in `src/i18n.rs`.
 3. Note: the DINOBYTE font only covers the CP437 character set.
+
+## License
+
+DungeonCraft is released under the [MIT License](LICENSE) – this covers the code, the generated music in `assets/music/` and the procedural graphics.
+The DINOBYTE font (`assets/dbyte_1x.png`) by mby is licensed separately under CC BY 4.0, see [CREDITS.md](CREDITS.md).
+