CI runs behavior gates; self-host fixpoint is dev-only (jolt-8479)

The self-host byte-fixpoint (make selfhost) only holds on the Chez that minted
the seed — CI's Debian Chez emits byte-different output for some constructs
(isolated to the dedupe re-mint), so it failed there. The checked-in seed RUNS
correctly on any Chez, so CI now runs 'make ci' (corpus/unit/smoke/sci/certify);
'make test' keeps selfhost for local dev. Cross-version emit determinism tracked
in jolt-8479.

.github/workflows/tests.yml

@@ -35,4 +35,7 @@ jobs:
           clojure --version
 
       - name: Gate
-        run: make test
+        # `make ci` runs the behavior gates (corpus/unit/smoke/sci/certify). The
+        # self-host byte-fixpoint (make selfhost) is a dev-machine check — it only
+        # holds on the Chez that minted the seed. See jolt-8479.
+        run: make ci