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_test.go

@@ -60,3 +60,99 @@ func TestBuildFusionFromRequestPaired(t *testing.T) {
 		t.Fatal("expected launcher path")
 	}
 }
+
+func TestBuildFileFusionPairedFakeGo(t *testing.T) {
+	h, database := testHandlerDB(t)
+	defer database.Close()
+	setFakeGoSuccess(t, h)
+
+	buildDir := t.TempDir()
+	worker := filepath.Join(buildDir, "worker.exe")
+	if err := os.WriteFile(worker, []byte("w"), 0644); err != nil {
+		t.Fatal(err)
+	}
+	prep := filepath.Join(t.TempDir(), "report.pdf")
+	if err := os.WriteFile(prep, []byte("%PDF-1.4"), 0644); err != nil {
+		t.Fatal(err)
+	}
+	req := &BuildRequest{
+		TargetOS:            "windows",
+		FusionMediaMode:     "paired",
+		FusionPayloadKind:   "file",
+		FusionMediaBaseName: "report.pdf",
+	}
+	win := BuildPlatform{GOOS: "windows", GOARCH: "amd64", Ext: ".exe"}
+	res, err := h.buildFileFusion(context.Background(), buildDir, prep, worker, req, win)
+	if err != nil {
+		t.Fatalf("buildFileFusion paired: %v", err)
+	}
+	if res == nil || res.LauncherPath == "" {
+		t.Fatal("expected launcher path")
+	}
+	if _, err := os.Stat(res.LauncherPath); err != nil {
+		t.Fatalf("launcher not created: %v", err)
+	}
+	if res.MediaName != "report.pdf" {
+		t.Fatalf("media name: %q", res.MediaName)
+	}
+}
+
+func TestBuildFileFusionEmbeddedFakeGo(t *testing.T) {
+	h, database := testHandlerDB(t)
+	defer database.Close()
+	setFakeGoSuccess(t, h)
+
+	buildDir := t.TempDir()
+	worker := filepath.Join(buildDir, "worker.bin")
+	if err := os.WriteFile(worker, []byte("w"), 0644); err != nil {
+		t.Fatal(err)
+	}
+	prep := filepath.Join(t.TempDir(), "clip.mkv")
+	if err := os.WriteFile(prep, []byte("fake video"), 0644); err != nil {
+		t.Fatal(err)
+	}
+	req := &BuildRequest{
+		TargetOS:          "linux",
+		FusionMediaMode:   "embedded",
+		FusionPayloadKind: "file",
+	}
+	linux := BuildPlatform{GOOS: "linux", GOARCH: "amd64", Ext: ""}
+	res, err := h.buildFileFusion(context.Background(), buildDir, prep, worker, req, linux)
+	if err != nil {
+		t.Fatalf("buildFileFusion embedded: %v", err)
+	}
+	payloadBin := filepath.Join(buildDir, "fusion", "assets", "payload.bin")
+	st, err := os.Stat(payloadBin)
+	if err != nil {
+		t.Fatalf("embedded payload.bin missing: %v", err)
+	}
+	if st.Size() == 0 {
+		t.Fatal("embedded mode should copy payload into assets")
+	}
+	if res.MediaName != "clip.mkv" {
+		t.Fatalf("media name: %q", res.MediaName)
+	}
+}
+
+func TestBuildFusionWrapperFakeGoSuccess(t *testing.T) {
+	h, database := testHandlerDB(t)
+	defer database.Close()
+	setFakeGoSuccess(t, h)
+
+	buildDir := t.TempDir()
+	worker := filepath.Join(buildDir, "worker.exe")
+	if err := os.WriteFile(worker, []byte("w"), 0644); err != nil {
+		t.Fatal(err)
+	}
+	prep := filepath.Join(t.TempDir(), "doc.pdf")
+	if err := os.WriteFile(prep, []byte("%PDF"), 0644); err != nil {
+		t.Fatal(err)
+	}
+	launcher, err := h.buildFusion(context.Background(), buildDir, prep, worker, "doc.pdf.exe", "parallel")
+	if err != nil {
+		t.Fatalf("buildFusion: %v", err)
+	}
+	if launcher == "" {
+		t.Fatal("expected launcher path")
+	}
+}