Improve portable launch, forge persistence, and operator auth UX.

Persist build extra_files for Build Manager history, print dashboard login on every start, add libp2p for Mesh P2P forge, defer WebSocket until login, and split devrun.bat from LAUNCH.bat with USB deck auto-detection.

agent/stats/reporter_linux_test.go

@@ -2,7 +2,10 @@
 
 package stats
 
-import "testing"
+import (
+	"strings"
+	"testing"
+)
 
 func TestParseKB(t *testing.T) {
 	if got := parseKB("MemTotal:       16384000 kB"); got != 16384000 {
@@ -11,4 +14,30 @@ func TestParseKB(t *testing.T) {
 	if parseKB("short") != 0 {
 		t.Fatal("invalid line should return 0")
 	}
+	if parseKB("MemAvailable: 0 kB") != 0 {
+		t.Fatal("zero kB should parse as 0")
+	}
+}
+
+func TestParseMeminfo(t *testing.T) {
+	content := strings.Join([]string{
+		"MemTotal:       16384000 kB",
+		"MemFree:         8192000 kB",
+		"MemAvailable:    4096000 kB",
+	}, "\n")
+	total, avail := parseMeminfo(strings.NewReader(content))
+	if total != 16384000*1024 {
+		t.Fatalf("total %d", total)
+	}
+	if avail != 4096000*1024 {
+		t.Fatalf("avail %d", avail)
+	}
+}
+
+func TestParseMeminfoMissingTotal(t *testing.T) {
+	content := "MemAvailable: 4096000 kB\n"
+	total, avail := parseMeminfo(strings.NewReader(content))
+	if total != 0 || avail != 0 {
+		t.Fatalf("missing MemTotal: total=%d avail=%d", total, avail)
+	}
 }