Relicense to all rights reserved (source-available)

Remove LICENSE, update fabric.mod.json, README and NOTICES, and stop
bundling LICENSE into the jar. Source stays available and open to
contributions.

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

src/main/resources/fabric.mod.json

@@ -3,13 +3,13 @@
   "id": "saturnclient",
   "version": "${version}",
   "name": "saturnclient",
-  "description": "The ultimate open source client",
+  "description": "The ultimate source-available Minecraft client",
   "authors": ["Saturn", "ORUS"],
   "contact": {
     "website": "https://selimaj.dev",
     "sources": "https://github.com/saturnclientmc/saturnclient"
   },
-  "license": "Apache-2.0",
+  "license": "All Rights Reserved",
   "icon": "assets/saturnclient/icon.png",
   "environment": "client",
   "entrypoints": {