Fix SATA discovery, add NVLink bridge detection, add infiniband-diags

- storage: add jsonInt64 dual-format unmarshaler to handle lsblk output
  change in util-linux 2.38 (LOG-SEC/PHY-SEC now emitted as JSON
  integers, not quoted strings); fixes SATA disks invisible on Debian 12
- pcie: detect NVLink bridge mezzanine CX-7 cards (Mellanox x2, no host
  net ifaces, DeviceName contains "NVLINK" in lspci -v) and mark them
  with device_class="NVLinkBridge"; escalate PCIe link speed downgrade to
  Critical for these cards (Gen3 on a fixed internal connector = hardware
  fault, not a transient warning)
- pcie: cross-reference nvidia-smi topo to capture NVLink bond counts and
  active status for all NVLink bridge cards
- packages: add infiniband-diags to ISO; provides ibstat required by
  nvidia-fabricmanager-start.sh to enumerate IB devices before FM launch
  (absence causes CUDA_ERROR_SYSTEM_NOT_READY)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

audit/internal/collector/storage.go

@@ -66,17 +66,41 @@ func collectStorage() []schema.HardwareStorage {
 	return result
 }
 
+// jsonInt64 accepts both a bare JSON number and a JSON-quoted number string.
+// lsblk -J emits LOG-SEC / PHY-SEC as integers on util-linux ≥ 2.37 (Debian 12)
+// but older versions emit them as strings. This type handles both.
+type jsonInt64 int64
+
+func (j *jsonInt64) UnmarshalJSON(data []byte) error {
+	// bare number: 512
+	var n int64
+	if err := json.Unmarshal(data, &n); err == nil {
+		*j = jsonInt64(n)
+		return nil
+	}
+	// quoted string: "512"
+	var s string
+	if err := json.Unmarshal(data, &s); err == nil {
+		n, err := strconv.ParseInt(strings.TrimSpace(s), 10, 64)
+		if err == nil {
+			*j = jsonInt64(n)
+		}
+		return nil
+	}
+	return nil // null or unexpected type — leave zero
+}
+
 // lsblkDevice is a minimal lsblk JSON record.
 type lsblkDevice struct {
-	Name   string `json:"name"`
-	Type   string `json:"type"`
-	Size   string `json:"size"`
-	Serial string `json:"serial"`
-	Model  string `json:"model"`
-	Tran   string `json:"tran"`
-	Hctl   string `json:"hctl"`
-	LogSec string `json:"log-sec"`
-	PhySec string `json:"phy-sec"`
+	Name   string   `json:"name"`
+	Type   string   `json:"type"`
+	Size   string   `json:"size"`
+	Serial string   `json:"serial"`
+	Model  string   `json:"model"`
+	Tran   string   `json:"tran"`
+	Hctl   string   `json:"hctl"`
+	LogSec jsonInt64 `json:"log-sec"`
+	PhySec jsonInt64 `json:"phy-sec"`
 }
 
 type lsblkRoot struct {
@@ -620,8 +644,8 @@ func applyStorageBlockGeometry(s *schema.HardwareStorage, dev lsblkDevice) {
 	if s == nil {
 		return
 	}
-	logical := parseStorageBytes(dev.LogSec)
-	physical := parseStorageBytes(dev.PhySec)
+	logical := int64(dev.LogSec)
+	physical := int64(dev.PhySec)
 	if logical <= 0 && physical <= 0 {
 		return
 	}