fix: improve assimp version output and unit test

src/helpers/printVersions.ts

@@ -121,7 +121,8 @@ if (process.env.NODE_ENV === "production") {
     }
 
     if (stdout) {
-      console.log(`assimp ${stdout.split("\n")[5]}`);
+      const firstLines = (stdout || "").split("\n");
+      console.log(`assimp ${firstLines[5] || firstLines[0] || ""}`);
     }
   });
 

tests/helpers/printVersions.test.ts

@@ -27,7 +27,7 @@ mock.module("node:child_process", () => ({
 
     // assimp's real output is multi-line; the source reads line index 5.
     if (cmd.startsWith("assimp")) {
-      cb(null, "l1\nl2\nl3\nl4\nl5\nassimp v1.0.0\n");
+      cb(null, "l1\nl2\nl3\nl4\nl5\nVersion 1.0.0 (GIT commit abc123)\n");
       return;
     }