Wire Iris jar shrink

- Wire the ProGuard shrink pass into the Bukkit artifact with the core, Bukkit plugin and NMS compile classpaths as library jars
- Map the fourteen SlimJar relocations so runtime-downloaded libraries resolve under their relocated names
- Add packaging/shrink.pro keeping the public API, Iris events, platform SPI, VolmLib integration contract and Bukkit event handler lists
- Lower maximumBukkitArtifactBytes to 7,600,000 so verifyBukkitArtifact enforces the same budget as the packaging gate
- Build VolmitSender.name() from the sender name instead of the relocated CommandSender.name() reference, which cannot resolve on Paper 26.2

core/src/main/java/art/arcane/iris/util/common/plugin/VolmitSender.java

@@ -359,7 +359,7 @@ public class VolmitSender implements CommandSender {
     @NotNull
     @Override
     public Component name() {
-        return s.name();
+        return Component.text(getName());
     }
 
     @Override