Rename to /scaletozero/{pin,unpin} and Pin/Unpin per review

Address review feedback:
- Path /system/standby/* implied VM-state mutation; rename to
  /scaletozero/{pin,unpin} so the operation is specific to the
  scale-to-zero gate.
- Interface methods DisablePin/EnablePin read as inverted; rename to
  Pin/Unpin for clarity.
- Rewrite openapi summary/description to be caller-focused (what it
  does, when to call, what pairs with).

Author: sjmiller609

server/cmd/api/api/scaletozero.go

@@ -0,0 +1,24 @@
+package api
+
+import (
+	"context"
+
+	"github.com/kernel/kernel-images/server/lib/logger"
+	oapi "github.com/kernel/kernel-images/server/lib/oapi"
+)
+
+func (s *ApiService) PinScaleToZero(ctx context.Context, _ oapi.PinScaleToZeroRequestObject) (oapi.PinScaleToZeroResponseObject, error) {
+	if err := s.stz.Pin(ctx); err != nil {
+		logger.FromContext(ctx).Error("failed to pin scale-to-zero", "err", err)
+		return oapi.PinScaleToZero500JSONResponse{InternalErrorJSONResponse: oapi.InternalErrorJSONResponse{Message: "failed to pin scale-to-zero"}}, nil
+	}
+	return oapi.PinScaleToZero204Response{}, nil
+}
+
+func (s *ApiService) UnpinScaleToZero(ctx context.Context, _ oapi.UnpinScaleToZeroRequestObject) (oapi.UnpinScaleToZeroResponseObject, error) {
+	if err := s.stz.Unpin(ctx); err != nil {
+		logger.FromContext(ctx).Error("failed to unpin scale-to-zero", "err", err)
+		return oapi.UnpinScaleToZero500JSONResponse{InternalErrorJSONResponse: oapi.InternalErrorJSONResponse{Message: "failed to unpin scale-to-zero"}}, nil
+	}
+	return oapi.UnpinScaleToZero204Response{}, nil
+}

server/cmd/api/api/standby.go

@@ -10,12 +10,12 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
-// TestStandbyDisableEnable exercises POST /system/standby/{disable,enable}
-// against the real built image. The unikraft control file does not exist
-// inside the docker test container, so the underlying scale-to-zero write
-// is a no-op — this test validates HTTP wiring, idempotency, and that the
-// scale-to-zero middleware coexists with the pin handlers.
-func TestStandbyDisableEnable(t *testing.T) {
+// TestScaleToZeroPinUnpin exercises POST /scaletozero/{pin,unpin} against the
+// real built image. The unikraft control file does not exist inside the docker
+// test container, so the underlying scale-to-zero write is a no-op — this test
+// validates HTTP wiring, idempotency, and that the scale-to-zero middleware
+// coexists with the pin handlers.
+func TestScaleToZeroPinUnpin(t *testing.T) {
 	t.Parallel()
 
 	if _, err := exec.LookPath("docker"); err != nil {
@@ -34,13 +34,13 @@ func TestStandbyDisableEnable(t *testing.T) {
 	client, err := c.APIClient()
 	require.NoError(t, err, "failed to create API client")
 
-	// Idempotent disable.
-	r1, err := client.DisableStandbyWithResponse(ctx)
-	require.NoError(t, err, "DisableStandby request failed")
+	// Idempotent pin.
+	r1, err := client.PinScaleToZeroWithResponse(ctx)
+	require.NoError(t, err, "PinScaleToZero request failed")
 	require.Equal(t, http.StatusNoContent, r1.StatusCode(), "unexpected status: %s body=%s", r1.Status(), string(r1.Body))
 
-	r2, err := client.DisableStandbyWithResponse(ctx)
-	require.NoError(t, err, "second DisableStandby request failed")
+	r2, err := client.PinScaleToZeroWithResponse(ctx)
+	require.NoError(t, err, "second PinScaleToZero request failed")
 	require.Equal(t, http.StatusNoContent, r2.StatusCode(), "unexpected status: %s body=%s", r2.Status(), string(r2.Body))
 
 	// Normal request must still flow while pinned (scaletozero middleware
@@ -49,12 +49,12 @@ func TestStandbyDisableEnable(t *testing.T) {
 	require.NoError(t, err, "ReadClipboard request failed while pinned")
 	require.Equal(t, http.StatusOK, readResp.StatusCode(), "unexpected read status while pinned: %s body=%s", readResp.Status(), string(readResp.Body))
 
-	// Idempotent enable.
-	r3, err := client.EnableStandbyWithResponse(ctx)
-	require.NoError(t, err, "EnableStandby request failed")
+	// Idempotent unpin.
+	r3, err := client.UnpinScaleToZeroWithResponse(ctx)
+	require.NoError(t, err, "UnpinScaleToZero request failed")
 	require.Equal(t, http.StatusNoContent, r3.StatusCode(), "unexpected status: %s body=%s", r3.Status(), string(r3.Body))
 
-	r4, err := client.EnableStandbyWithResponse(ctx)
-	require.NoError(t, err, "second EnableStandby request failed")
+	r4, err := client.UnpinScaleToZeroWithResponse(ctx)
+	require.NoError(t, err, "second UnpinScaleToZero request failed")
 	require.Equal(t, http.StatusNoContent, r4.StatusCode(), "unexpected status: %s body=%s", r4.Status(), string(r4.Body))
 }