fix(inventory): read GPU model from device field, not vendor field

`lspci -D -mm -nn` prefixes every line with the PCI address as a bare
token before the three quoted class/vendor/device fields, so the
device name sits at fields[3] — not fields[2], which is the vendor.
The probe was indexing [2] and recording every GPU's model as its
vendor string ("Intel Corporation" instead of "Alder Lake-N [UHD
Graphics]"), which made every SpecValidate mismatch on real hosts
once the expected spec named the device.

Extract the per-line parse into parseLspciMMLine, handle both the
modern -D layout (addr + class/vendor/device) and the legacy
layout without an address prefix (class/vendor/device), and cover
both paths plus the non-GPU-class skip in inventory_test.go.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

agent/probes/inventory_test.go

@@ -153,6 +153,57 @@ Memory Device
 	}
 }
 
+func TestParseLspciMMLine(t *testing.T) {
+	cases := []struct {
+		name        string
+		line        string
+		wantAddr    string
+		wantModel   string
+		wantSkipped bool
+	}{
+		{
+			name:      "with -D, N95 integrated GPU",
+			line:      `0000:00:02.0 "VGA compatible controller [0300]" "Intel Corporation [8086]" "Alder Lake-N [UHD Graphics] [46d0]" -r1c "Intel Corporation [8086]" "Device [7270]"`,
+			wantAddr:  "0000:00:02.0",
+			wantModel: "Alder Lake-N [UHD Graphics]",
+		},
+		{
+			name:      "without -D, legacy three-quoted layout",
+			line:      `"VGA compatible controller" "NVIDIA Corporation" "GP104 [GeForce GTX 1080]"`,
+			wantAddr:  "",
+			wantModel: "GP104 [GeForce GTX 1080]",
+		},
+		{
+			name:      "3D controller class also picked up",
+			line:      `0000:01:00.0 "3D controller [0302]" "NVIDIA Corporation [10de]" "TU104GL [Tesla T4] [1eb8]"`,
+			wantAddr:  "0000:01:00.0",
+			wantModel: "TU104GL [Tesla T4]",
+		},
+		{
+			name:        "non-GPU class is skipped",
+			line:        `0000:01:00.0 "Ethernet controller [0200]" "Intel Corporation [8086]" "I350 [1521]"`,
+			wantSkipped: true,
+		},
+	}
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			addr, model := parseLspciMMLine(tc.line)
+			if tc.wantSkipped {
+				if model != "" {
+					t.Fatalf("expected skip, got addr=%q model=%q", addr, model)
+				}
+				return
+			}
+			if addr != tc.wantAddr {
+				t.Errorf("addr: got %q want %q", addr, tc.wantAddr)
+			}
+			if model != tc.wantModel {
+				t.Errorf("model: got %q want %q", model, tc.wantModel)
+			}
+		})
+	}
+}
+
 func TestParseLspciVerbose(t *testing.T) {
 	sample := `01:00.0 VGA compatible controller: NVIDIA Corporation
 	Subsystem: ASUSTeK