fix(pcie): stop misclassifying same-vendor non-GPU devices as GPUs

matchesGPUVendor (sat_overlay.go) matched any PCIe DeviceClass containing
the substring "Controller" instead of the actual GPU classes, so a
same-vendor non-GPU device (e.g. an NVIDIA-branded NIC/storage controller)
with a degraded PCIe link surfaced as a pcie:gpu:<vendor> alarm on the
Hardware Summary/webui.

isGPUDevice (app_format.go) had the same bug via a different path: an
"any NVIDIA-vendor device is a GPU" fallback that could inflate the
"GPU: N x <model>" audit summary line with non-GPU companion devices
(NVSwitch/NVLink bridges, etc).

Both now defer to collector.IsGPUClass (exported from the previously
unexported isGPUClass), the canonical exact-match classifier already used
by amdgpu.go — removing the duplicated/incorrect class checks instead of
reimplementing them. Also dedup two more locally-duplicated classifiers
within webui (which doesn't import collector by convention): NIC-class
matching (pages.go/page_topo.go) and GPU-class matching in
page_validate.go now share one copy per package instead of being
reimplemented per file.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

audit/internal/webui/pages.go

@@ -560,16 +560,21 @@ func hwDescribePSU(hw schema.HardwareSnapshot) string {
 	return fmt.Sprintf("%d× PSU", n)
 }
 
+// isNICDeviceClass reports whether a normalized PCIe DeviceClass string
+// (see collector.mapPCIeDeviceClass) identifies a NIC/HBA-class device.
+// webui does not import collector (see the "Classification helpers" note
+// in page_topo.go), so this mirrors collector.isNICClass locally.
+func isNICDeviceClass(class string) bool {
+	c := strings.ToLower(strings.TrimSpace(class))
+	return c == "ethernetcontroller" || c == "networkcontroller" || strings.Contains(c, "fibrechannel")
+}
+
 // hwDescribeNIC returns a summary like "2× Mellanox ConnectX-6".
 func hwDescribeNIC(hw schema.HardwareSnapshot) string {
 	counts := map[string]int{}
 	order := []string{}
 	for _, dev := range hw.PCIeDevices {
-		isNIC := false
-		if dev.DeviceClass != nil {
-			c := strings.ToLower(strings.TrimSpace(*dev.DeviceClass))
-			isNIC = c == "ethernetcontroller" || c == "networkcontroller" || strings.Contains(c, "fibrechannel")
-		}
+		isNIC := dev.DeviceClass != nil && isNICDeviceClass(*dev.DeviceClass)
 		if !isNIC && len(dev.MacAddresses) == 0 {
 			continue
 		}