feat(world): find systems based on inheritance

.changeset/small-horses-own.md

@@ -0,0 +1,5 @@
+---
+"@latticexyz/world": patch
+---
+
+Support systems without the System suffix by adding them to the MUD config.

packages/world/ts/node/getSystemContracts.ts

@@ -22,10 +22,22 @@ export async function getSystemContracts({
     pattern: path.join(config.sourceDirectory, "**"),
   });
 
+  // Get systems from the top-level systems object
+  const topLevelSystems = Object.keys(config.systems);
+
+  // Get systems from namespaces
+  const namespaceSystems = Object.values(config.namespaces || {}).flatMap((namespace) =>
+    Object.keys(namespace.systems || {}),
+  );
+
+  // Combine both sets of systems
+  const configSystems = [...topLevelSystems, ...namespaceSystems];
+
   return solidityFiles
     .filter(
       (file) =>
-        file.basename.endsWith("System") &&
+        // Include files with the System suffix and files defined in config
+        (file.basename.endsWith("System") || configSystems.includes(file.basename)) &&
         // exclude the base System contract
         file.basename !== "System" &&
         // exclude interfaces