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.

server/internal/builder/test_helper_test.go

@@ -67,3 +67,52 @@ func setFakeGoFail(t *testing.T, h *Handler) {
 	}
 	h.goBinPath = p
 }
+
+// setFakeGoSuccess points goBinPath at a script that writes the -o output and exits 0.
+func setFakeGoSuccess(t *testing.T, h *Handler) {
+	t.Helper()
+	dir := t.TempDir()
+	if runtime.GOOS == "windows" {
+		p := filepath.Join(dir, "go-ok.bat")
+		script := "@echo off\r\nsetlocal EnableDelayedExpansion\r\nset \"OUT=\"\r\n" +
+			":loop\r\nif \"%~1\"==\"\" goto done\r\nif /I \"%~1\"==\"-o\" (\r\n" +
+			"  set \"OUT=%~2\"\r\n  shift\r\n  shift\r\n  goto loop\r\n)\r\n" +
+			"shift\r\ngoto loop\r\n:done\r\n" +
+			"if defined OUT (\r\n" +
+			"  for %%I in (\"!OUT!\") do if not exist \"%%~dpI\" mkdir \"%%~dpI\" 2>nul\r\n" +
+			"  echo fake>\"!OUT!\"\r\n" +
+			")\r\nexit /b 0\r\n"
+		if err := os.WriteFile(p, []byte(script), 0644); err != nil {
+			t.Fatal(err)
+		}
+		h.goBinPath = p
+		return
+	}
+	p := filepath.Join(dir, "go-ok.sh")
+	script := "#!/bin/sh\nOUT=\"\"\nwhile [ $# -gt 0 ]; do\n" +
+		"  if [ \"$1\" = \"-o\" ]; then OUT=\"$2\"; shift; fi\n  shift\n" +
+		"done\nif [ -n \"$OUT\" ]; then mkdir -p \"$(dirname \"$OUT\")\"; echo fake > \"$OUT\"; fi\nexit 0\n"
+	if err := os.WriteFile(p, []byte(script), 0755); err != nil {
+		t.Fatal(err)
+	}
+	h.goBinPath = p
+}
+
+// setFakeGoSleep points goBinPath at a script that blocks long enough to test cancellation.
+func setFakeGoSleep(t *testing.T, h *Handler) {
+	t.Helper()
+	dir := t.TempDir()
+	if runtime.GOOS == "windows" {
+		p := filepath.Join(dir, "go-sleep.bat")
+		if err := os.WriteFile(p, []byte("@echo off\r\nping 127.0.0.1 -n 8 >nul\r\nexit /b 0\r\n"), 0644); err != nil {
+			t.Fatal(err)
+		}
+		h.goBinPath = p
+		return
+	}
+	p := filepath.Join(dir, "go-sleep.sh")
+	if err := os.WriteFile(p, []byte("#!/bin/sh\nsleep 8\nexit 0\n"), 0755); err != nil {
+		t.Fatal(err)
+	}
+	h.goBinPath = p
+}