fix: claude affinity cache counter (#2980)

* fix: claude affinity cache counter

* fix: claude affinity cache counter

* fix: stabilize cache usage stats format and simplify modal rendering

relay/common/relay_info_test.go

@@ -0,0 +1,40 @@
+package common
+
+import (
+	"testing"
+
+	"github.com/QuantumNous/new-api/types"
+	"github.com/stretchr/testify/require"
+)
+
+func TestRelayInfoGetFinalRequestRelayFormatPrefersExplicitFinal(t *testing.T) {
+	info := &RelayInfo{
+		RelayFormat:             types.RelayFormatOpenAI,
+		RequestConversionChain:  []types.RelayFormat{types.RelayFormatOpenAI, types.RelayFormatClaude},
+		FinalRequestRelayFormat: types.RelayFormatOpenAIResponses,
+	}
+
+	require.Equal(t, types.RelayFormat(types.RelayFormatOpenAIResponses), info.GetFinalRequestRelayFormat())
+}
+
+func TestRelayInfoGetFinalRequestRelayFormatFallsBackToConversionChain(t *testing.T) {
+	info := &RelayInfo{
+		RelayFormat:            types.RelayFormatOpenAI,
+		RequestConversionChain: []types.RelayFormat{types.RelayFormatOpenAI, types.RelayFormatClaude},
+	}
+
+	require.Equal(t, types.RelayFormat(types.RelayFormatClaude), info.GetFinalRequestRelayFormat())
+}
+
+func TestRelayInfoGetFinalRequestRelayFormatFallsBackToRelayFormat(t *testing.T) {
+	info := &RelayInfo{
+		RelayFormat: types.RelayFormatGemini,
+	}
+
+	require.Equal(t, types.RelayFormat(types.RelayFormatGemini), info.GetFinalRequestRelayFormat())
+}
+
+func TestRelayInfoGetFinalRequestRelayFormatNilReceiver(t *testing.T) {
+	var info *RelayInfo
+	require.Equal(t, types.RelayFormat(""), info.GetFinalRequestRelayFormat())
+}