SMART: add eMMC health via sysfs (#1736)

* SMART: add eMMC health via sysfs

Read eMMC wear/EOL indicators from /sys/class/block/mmcblk*/device and expose in SMART device list. Includes mocked sysfs tests and UI tweaks for unknown temps.

* small optimizations for emmc scan and parsing

* smart: keep smartctl optional only for Linux hosts with eMMC

* update smart alerts to handle warning state

* refactor: rename binPath to smartctlPath and replace hasSmartctl with smartctlPath checks

---------

Co-authored-by: henrygd <hank@henrygd.me>

agent/emmc_linux_test.go

@@ -0,0 +1,80 @@
+//go:build linux
+
+package agent
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/henrygd/beszel/internal/entities/smart"
+)
+
+func TestEmmcMockSysfsScanAndCollect(t *testing.T) {
+	tmp := t.TempDir()
+	prev := emmcSysfsRoot
+	emmcSysfsRoot = tmp
+	t.Cleanup(func() { emmcSysfsRoot = prev })
+
+	// Fake: /sys/class/block/mmcblk0
+	mmcDeviceDir := filepath.Join(tmp, "class", "block", "mmcblk0", "device")
+	mmcQueueDir := filepath.Join(tmp, "class", "block", "mmcblk0", "queue")
+	if err := os.MkdirAll(mmcDeviceDir, 0o755); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.MkdirAll(mmcQueueDir, 0o755); err != nil {
+		t.Fatal(err)
+	}
+
+	write := func(path, content string) {
+		t.Helper()
+		if err := os.WriteFile(path, []byte(content), 0o644); err != nil {
+			t.Fatal(err)
+		}
+	}
+
+	write(filepath.Join(mmcDeviceDir, "pre_eol_info"), "0x02\n")
+	write(filepath.Join(mmcDeviceDir, "life_time"), "0x04 0x05\n")
+	write(filepath.Join(mmcDeviceDir, "name"), "H26M52103FMR\n")
+	write(filepath.Join(mmcDeviceDir, "serial"), "01234567\n")
+	write(filepath.Join(mmcDeviceDir, "prv"), "0x08\n")
+	write(filepath.Join(mmcQueueDir, "logical_block_size"), "512\n")
+	write(filepath.Join(tmp, "class", "block", "mmcblk0", "size"), "1024\n") // sectors
+
+	devs := scanEmmcDevices()
+	if len(devs) != 1 {
+		t.Fatalf("scanEmmcDevices() = %d devices, want 1", len(devs))
+	}
+	if devs[0].Name != "/dev/mmcblk0" || devs[0].Type != "emmc" {
+		t.Fatalf("scanEmmcDevices()[0] = %+v, want Name=/dev/mmcblk0 Type=emmc", devs[0])
+	}
+
+	sm := &SmartManager{SmartDataMap: map[string]*smart.SmartData{}}
+	ok, err := sm.collectEmmcHealth(devs[0])
+	if err != nil || !ok {
+		t.Fatalf("collectEmmcHealth() = (ok=%v, err=%v), want (true,nil)", ok, err)
+	}
+	if len(sm.SmartDataMap) != 1 {
+		t.Fatalf("SmartDataMap len=%d, want 1", len(sm.SmartDataMap))
+	}
+	var got *smart.SmartData
+	for _, v := range sm.SmartDataMap {
+		got = v
+		break
+	}
+	if got == nil {
+		t.Fatalf("SmartDataMap value nil")
+	}
+	if got.DiskType != "emmc" || got.DiskName != "/dev/mmcblk0" {
+		t.Fatalf("disk fields = (type=%q name=%q), want (emmc,/dev/mmcblk0)", got.DiskType, got.DiskName)
+	}
+	if got.SmartStatus != "WARNING" {
+		t.Fatalf("SmartStatus=%q, want WARNING", got.SmartStatus)
+	}
+	if got.SerialNumber != "01234567" || got.ModelName == "" || got.Capacity == 0 {
+		t.Fatalf("identity fields = (model=%q serial=%q cap=%d), want non-empty model, serial 01234567, cap>0", got.ModelName, got.SerialNumber, got.Capacity)
+	}
+	if len(got.Attributes) < 3 {
+		t.Fatalf("attributes len=%d, want >= 3", len(got.Attributes))
+	}
+}