test(observer-status): set process.exitCode so the summary always flushes

Review feedback on #2878. stdout is async when it is a pipe, which is exactly
how tests/run-all.js runs these files, and process.exit() does not wait for
pending writes — so exiting that way can drop the Passed:/Failed: lines the
aggregator totals, defeating the previous commit. The sibling
tests/ci/ito-*-skill.test.js files already use process.exitCode.

Still exits 1 on a broken counter (Passed: 4, Failed: 7) and 0 when clean.

tests/skills/observer-status-instinct-count.test.js

@@ -204,7 +204,10 @@ function main() {
 
   console.log(`\n  Passed: ${passed}`);
   console.log(`  Failed: ${failed}`);
-  if (failed > 0) process.exit(1);
+  // exitCode, not exit(1): stdout is async when it is a pipe, which is how
+  // tests/run-all.js runs this, and process.exit() does not wait for pending
+  // writes — it could drop the two lines above, which the aggregator totals.
+  if (failed > 0) process.exitCode = 1;
 }
 
 main();