Align console behavior with operator routing and image workflow expectations

Constraint: Must preserve current exchange-rate logic, same-group routing boundary, and temporary image-file behavior while fixing UX-visible inconsistencies.
Rejected: Large frontend chunk refactor | introduced risky circular chunking and did not improve deliverability for this rollout.
Confidence: medium
Scope-risk: moderate
Directive: Keep channel failover constrained to the selected group and preserve Beijing-day semantics for user cache dashboard metrics.
Tested: go test ./controller ./model ./service ./common -count=1; npm run build; remote smoke on source deployment at http://38.76.218.56:18081/ plus /api/status and /api/image-studio/settings.
Not-tested: Browser-driven end-to-end verification of every console page interaction.

model/log_dashboard_metrics_test.go

@@ -0,0 +1,40 @@
+package model
+
+import (
+	"testing"
+	"time"
+)
+
+func TestGetDashboardDayStartUnixUsesShanghai(t *testing.T) {
+	utcTime := time.Date(2026, 5, 5, 0, 30, 0, 0, time.UTC)
+	got := getDashboardDayStartUnix(utcTime)
+
+	want := time.Date(2026, 5, 5, 0, 0, 0, 0, dashboardMetricsLocation).Unix()
+	if got != want {
+		t.Fatalf("expected Shanghai day start %d, got %d", want, got)
+	}
+}
+
+func TestAccumulateCacheMetrics(t *testing.T) {
+	row := cacheMetricRow{
+		PromptTokens: 100,
+		Other:        `{"cache_read_tokens":40,"cache_write_tokens":10}`,
+	}
+	metrics := CacheDashboardMetrics{}
+
+	accumulateCacheMetrics(&metrics, row)
+	finalizeCacheMetrics(&metrics)
+
+	if metrics.CacheReadTokens != 40 {
+		t.Fatalf("expected cache read 40, got %d", metrics.CacheReadTokens)
+	}
+	if metrics.CacheWriteTokens != 10 {
+		t.Fatalf("expected cache write 10, got %d", metrics.CacheWriteTokens)
+	}
+	if metrics.CacheTokens != 50 {
+		t.Fatalf("expected cache tokens 50, got %d", metrics.CacheTokens)
+	}
+	if metrics.CacheHitRate <= 0 {
+		t.Fatalf("expected positive hit rate, got %f", metrics.CacheHitRate)
+	}
+}