perf(pack): add Clumps for XP-orb merging

Reduces XP orb entity count, cutting entity packets sent to clients and server tick cost.

mods/clumps.pw.toml

@@ -0,0 +1,13 @@
+name = "Clumps"
+filename = "Clumps-neoforge-1.21.1-19.0.0.1.jar"
+side = "both"
+
+[download]
+url = "https://cdn.modrinth.com/data/Wnxd13zP/versions/jo7lDoK4/Clumps-neoforge-1.21.1-19.0.0.1.jar"
+hash-format = "sha512"
+hash = "314d8d8e640d73041f27e0f3f2cad7aad8b4c77dbd7fb31700ef7760362261f77085eed5289555c725d99c3f47a114e7290cd608f39c9f0f12ef74958463bdcc"
+
+[update]
+[update.modrinth]
+mod-id = "Wnxd13zP"
+version = "jo7lDoK4"