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/fusion_media_test.go

@@ -1,6 +1,7 @@
 package builder
 
 import (
+	"context"
 	"encoding/json"
 	"os"
 	"path/filepath"
@@ -135,6 +136,47 @@ func TestPrepareFusionProjectMissingSource(t *testing.T) {
 	}
 }
 
+func TestPrepareFusionProjectSuccess(t *testing.T) {
+	h, database := testHandlerDB(t)
+	defer database.Close()
+
+	fusionDir, err := h.prepareFusionProject(t.TempDir(), "prep_first", "file", "paired", "report.pdf")
+	if err != nil {
+		t.Fatalf("prepareFusionProject: %v", err)
+	}
+	main, err := os.ReadFile(filepath.Join(fusionDir, "main.go"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	body := string(main)
+	for _, want := range []string{`runOrder      = "prep_first"`, `payloadKind   = "file"`, `mediaFileName = "report.pdf"`} {
+		if !strings.Contains(body, want) {
+			t.Fatalf("patched main missing %q:\n%s", want, body)
+		}
+	}
+	if _, err := os.Stat(filepath.Join(fusionDir, "go.mod")); err != nil {
+		t.Fatalf("fusion go.mod not copied: %v", err)
+	}
+}
+
+func TestBuildFileFusionMissingWorker(t *testing.T) {
+	h, database := testHandlerDB(t)
+	defer database.Close()
+	setFakeGoSuccess(t, h)
+
+	buildDir := t.TempDir()
+	prep := filepath.Join(t.TempDir(), "report.pdf")
+	if err := os.WriteFile(prep, []byte("%PDF"), 0644); err != nil {
+		t.Fatal(err)
+	}
+	req := &BuildRequest{FusionMediaMode: "paired", FusionPayloadKind: "file"}
+	win := BuildPlatform{GOOS: "windows", GOARCH: "amd64", Ext: ".exe"}
+	_, err := h.buildFileFusion(context.Background(), buildDir, prep, filepath.Join(buildDir, "missing.exe"), req, win)
+	if err == nil {
+		t.Fatal("expected worker copy failure")
+	}
+}
+
 func TestPublishFusionDeliverable(t *testing.T) {
 	root := t.TempDir()
 	h := &Handler{projectRoot: root}