fix(parser): expose NVIDIA HGX tray/baseboard identity separately from vendor carrier FRU

Inspur/Kaytus onekeylog dumps only exposed the mechanical carrier FRU serial
(component/fru.txt Board Product) as board identity. That serial doesn't
change when the actual NVIDIA HGX baseboard (SXM+NVSwitch "delta board") is
swapped, causing false "board unchanged" conclusions. Parse the real HGX
tray/baseboard Model/PartNumber/SerialNumber triples from
HGX_HWInfo_FWVersion.log into a new HardwareConfig.HGX field, and normalize
Redfish's NA/N-A placeholders to empty across HGX identity parsing.

Closes #21

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

internal/parser/vendors/inspur/parser.go

@@ -278,6 +278,7 @@ func (p *Parser) Parse(files []parser.ExtractedFile) (*models.AnalysisResult, er
 	if f := parser.FindFileByName(files, "HGX_HWInfo_FWVersion.log"); f != nil && result.Hardware != nil {
 		enrichGPUsFromHGXHWInfo(f.Content, result.Hardware)
 		appendHGXFirmwareFromHWInfo(f.Content, result.Hardware)
+		result.Hardware.HGX = parseHGXIdentity(f.Content)
 	}
 
 	// Mark problematic GPUs from IDL errors like "BIOS miss F_GPU6".