ci: drop the schedule triggers, race and fuzz run on dispatch alone

Assisted-by: GLM 5.3

.gitea/workflows/test.yml

@@ -2,8 +2,8 @@
 #
 # The gates are the ones the justfile's `gates` recipe runs, minus race: the shared
 # runner box cannot afford the race detector on every push. Race has its own
-# pipeline, dispatched by hand and swept nightly, and the local `just gates`
-# runs it once per task. The box is one core and 2 GB beside Gitea, so
+# pipeline, dispatched by hand, and the local `just gates` runs it once per
+# task. The box is one core and 2 GB beside Gitea, so
 # parallelism is bounded on purpose and everything runs in one job. Extra jobs would
 # duplicate the checkout, the Go setup and the dependency download three times without
 # buying any parallelism.