Add GPU serial number extraction for NVIDIA diagnostics

Parse inventory/output.log to extract GPU serial numbers from lspci output,
expose them via serials API, and add GPU category to web UI.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

internal/parser/vendors/nvidia/inventory_log_test.go

@@ -0,0 +1,87 @@
+package nvidia
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"git.mchus.pro/mchus/logpile/internal/parser"
+)
+
+func TestParseInventoryLog(t *testing.T) {
+	// Test with the real archive
+	archivePath := filepath.Join("../../../../example", "A514359X5A09844_logs-20260115-151707.tar")
+
+	// Check if file exists
+	if _, err := os.Stat(archivePath); os.IsNotExist(err) {
+		t.Skip("Test archive not found, skipping test")
+	}
+
+	// Extract files from archive
+	files, err := parser.ExtractArchive(archivePath)
+	if err != nil {
+		t.Fatalf("Failed to extract archive: %v", err)
+	}
+
+	// Find inventory/output.log
+	var inventoryLog *parser.ExtractedFile
+	for _, f := range files {
+		if strings.Contains(f.Path, "inventory/output.log") {
+			inventoryLog = &f
+			break
+		}
+	}
+
+	if inventoryLog == nil {
+		t.Fatal("inventory/output.log not found")
+	}
+
+	content := string(inventoryLog.Content)
+
+	// Test devname regex
+	t.Log("Testing devname extraction:")
+	lines := strings.Split(content, "\n")
+	for i, line := range lines {
+		if strings.Contains(line, "devname=") && strings.Contains(line, "fieldiag") {
+			t.Logf("Line %d: Found fieldiag command", i)
+			matches := devnameRegex.FindAllStringSubmatch(line, -1)
+			t.Logf("  Found %d devname matches", len(matches))
+			for _, match := range matches {
+				if len(match) == 3 {
+					t.Logf("    PCI: %s -> Slot: %s", match[1], match[2])
+				}
+			}
+			break
+		}
+	}
+
+	// Test lspci regex
+	t.Log("\nTesting lspci BDF extraction:")
+	serialCount := 0
+	bdfCount := 0
+	for i, line := range lines {
+		// Check for lines that look like lspci headers
+		if strings.Contains(line, "3D controller") && strings.Contains(line, "NVIDIA") {
+			t.Logf("Line %d: Potential lspci line: %q (starts with: %q)", i, line[:min(80, len(line))], line[:min(10, len(line))])
+			if match := pciBDFRegex.FindStringSubmatch(line); len(match) > 1 {
+				bdfCount++
+				t.Logf("  -> Matched BDF: %s", match[1])
+			} else {
+				t.Logf("  -> NO MATCH")
+			}
+		}
+		if match := gpuSerialRegex.FindStringSubmatch(line); len(match) > 1 {
+			serialCount++
+		}
+	}
+	t.Logf("\nTotal BDFs found: %d", bdfCount)
+	t.Logf("Total serials found: %d", serialCount)
+}
+
+func min(a, b int) int {
+	if a < b {
+		return a
+	}
+	return b
+}