feat(monitor): show backup tunnel latencies (#535)

Closes #508

go-backend/internal/store/repo/repository_monitoring_test.go

@@ -132,3 +132,31 @@ func TestUpsertTunnelMetricBucketsIsSafeUnderConcurrency(t *testing.T) {
 		t.Fatalf("expected bytesOut %d, got %d", wantOut, rows[0].BytesOut)
 	}
 }
+
+func TestGetLatestTunnelQualitiesIncludesChainDetails(t *testing.T) {
+	r, err := Open(":memory:")
+	if err != nil {
+		t.Fatalf("open repo: %v", err)
+	}
+	defer r.Close()
+
+	if err := r.InsertTunnelQuality(&model.TunnelQuality{
+		TunnelID:     7,
+		Timestamp:    time.Now().UnixMilli(),
+		Success:      1,
+		ChainDetails: `{"primaryPath":[],"candidateHops":[{"fromNodeId":10,"toNodeId":31}]}`,
+	}); err != nil {
+		t.Fatalf("insert tunnel quality: %v", err)
+	}
+
+	items, err := r.GetLatestTunnelQualities()
+	if err != nil {
+		t.Fatalf("get latest tunnel qualities: %v", err)
+	}
+	if len(items) != 1 {
+		t.Fatalf("expected one latest tunnel quality, got %+v", items)
+	}
+	if items[0].ChainDetails == "" {
+		t.Fatalf("expected chain details in latest quality row, got %+v", items[0])
+	}
+}

go-backend/internal/store/repo/repository_tunnel_quality.go

@@ -44,7 +44,8 @@ func (r *Repository) GetLatestTunnelQualities() ([]model.TunnelQuality, error) {
 	// Use window function (works on modern SQLite 3.25+ and PostgreSQL).
 	q := `
 		SELECT id, tunnel_id, entry_to_exit_latency, exit_to_bing_latency,
-		       entry_to_exit_loss, exit_to_bing_loss, success, error_message, timestamp
+		       entry_to_exit_loss, exit_to_bing_loss, success, error_message, timestamp,
+		       chain_details
 		FROM (
 			SELECT *, ROW_NUMBER() OVER (PARTITION BY tunnel_id ORDER BY timestamp DESC, id DESC) AS rn
 			FROM tunnel_quality