test: isolate workerprobe heartbeat state

Author: ddx-checkpoint

CHANGELOG.md

@@ -11,8 +11,8 @@ the optional security scans no longer make the workflow invalid when their
 secrets are unset. The frontend dependency graph also overrides `devalue` to a
 patched version so the high-severity Bun audit finding is cleared. Command test
 fixtures now suppress background update checks so CI temp-directory cleanup is
-not racing asynchronous network/cache work. The workerprobe integration test
-also isolates server state before constructing its test server, preventing CI's
+not racing asynchronous network/cache work. Workerprobe integration tests also
+isolate server state before constructing test servers, preventing CI's
 state-pollution guard from seeing worker fixture projects.
 
 ### Fixed: autonomous provider-connectivity recovery

cli/internal/agent/workerprobe/liveness_heartbeat_test.go

@@ -30,6 +30,10 @@ func TestWorkerProbe_PeriodicHeartbeatRefreshesServerLastEventAt(t *testing.T) {
 
 	projectRoot := t.TempDir()
 
+	// Isolate server state before constructing the server. New() registers
+	// the project immediately.
+	t.Setenv("XDG_DATA_HOME", t.TempDir())
+
 	srv := serverpkg.New(":0", projectRoot)
 	ts := httptest.NewServer(srv.Handler())
 	defer ts.Close()