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_darwin_test.go

@@ -0,0 +1,25 @@
+//go:build darwin
+
+package stats
+
+import "testing"
+
+func TestParseVmStatFreePages(t *testing.T) {
+	out := `Mach Virtual Memory Statistics: (page size of 4096 bytes)
+Pages free:                               12345.
+Pages active:                            67890.
+`
+	if got := parseVmStatFreePages(out); got != 12345 {
+		t.Fatalf("got %d", got)
+	}
+	if parseVmStatFreePages("no free pages here") != 0 {
+		t.Fatal("missing line should return 0")
+	}
+}
+
+func TestParseVmStatFreeBytes(t *testing.T) {
+	out := "Pages free:                               1000.\n"
+	if got := parseVmStatFreeBytes(out); got != 1000*4096 {
+		t.Fatalf("got %d", got)
+	}
+}