Two-socket machines: Hardware and Top show each CPU, not one with every core

Hardware counts CPUs, cores and threads per CPU. Top groups threads under a row
per socket, reads each core's temperature from its own socket's coretemp chip,
and the CPU temperature is the hotter package.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/metrics/cputemp_test.go

@@ -0,0 +1,16 @@
+package metrics
+
+import "testing"
+
+// a two-socket board: two coretemp chips, and the CPU's temperature is the hotter package
+func TestCPUTempHottestPackage(t *testing.T) {
+	temps := []Temp{
+		{Chip: "coretemp", Label: "Core 0", C: 31},
+		{Chip: "coretemp", Label: "Core 0", C: 44, Pkg: 1},
+		{Chip: "coretemp", Label: "Package id 0", C: 35},
+		{Chip: "coretemp", Label: "Package id 1", C: 41, Pkg: 1},
+	}
+	if got := cpuTemp(temps); got != 41 {
+		t.Fatalf("cpuTemp = %v, want 41", got)
+	}
+}