docs: add LunarCore to server architecture credits

README_EN.md

@@ -89,6 +89,9 @@ Priority Order: **Environment Variables > `server.local.json` > `server.json`**
   - Reference Go server emulator providing dispatch architecture, gateway connection management, and base packet handler implementations.
   - Upstream opcode and Command ID definitions (`protocol/proto/upstream_cmdids.go`).
 
+- **LunarCore ([Melledy/LunarCore](https://github.com/Melledy/LunarCore))**:
+  - Pioneering Java-based Star Rail game server emulator by Melledy and contributors — the industry-standard reference for battle mechanics, packet definitions, and gacha probability curves.
+
 - **FreeSR Team**:
   - Foundational player JSON schema specifications (`freesr-data.json`) utilized for loading and persisting player roster and inventory data.