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/cpu_windows.go

@@ -17,6 +17,20 @@ func filetimeToUint64(ft filetime) uint64 {
 	return (uint64(ft.HighDateTime) << 32) | uint64(ft.LowDateTime)
 }
 
+func cpuBusyPercentFromDeltas(idleDelta, totalDelta float64) float64 {
+	if totalDelta <= 0 {
+		return 0
+	}
+	busyPct := (1.0 - idleDelta/totalDelta) * 100
+	if busyPct < 0 {
+		return 0
+	}
+	if busyPct > 100 {
+		return 100
+	}
+	return busyPct
+}
+
 func (r *Reporter) SystemCPUPercent() float64 {
 	r.mu.Lock()
 	defer r.mu.Unlock()
@@ -49,15 +63,5 @@ func (r *Reporter) SystemCPUPercent() float64 {
 	r.lastKernel = kernelTicks
 	r.lastUser = userTicks
 
-	if totalDelta <= 0 {
-		return 0
-	}
-	busyPct := (1.0 - idleDelta/totalDelta) * 100
-	if busyPct < 0 {
-		return 0
-	}
-	if busyPct > 100 {
-		return 100
-	}
-	return busyPct
+	return cpuBusyPercentFromDeltas(idleDelta, totalDelta)
 }