fix(tray): compile the menu bar out of CGO-disabled builds (#94)

fyne.io/systray's macOS backend is Objective-C and needs cgo, so the
release job (goreleaser cross-compiling darwin with CGO_ENABLED=0) failed
to link it ("undefined: nativeLoop", ...).

Guard the darwin tray behind `darwin && cgo` and add a `darwin && !cgo`
stub that reports the menu bar needs a cgo build (mirroring the existing
non-macOS stub). CGO-disabled cross-builds now compile; a normal
`go build`/`go install` on macOS (cgo on by default) still gets the tray.

Author: kriuchkov

internal/app/commands/tray_darwin.go

@@ -1,4 +1,4 @@
-//go:build darwin
+//go:build darwin && cgo
 
 package commands
 

internal/app/commands/tray_darwin_nocgo.go

@@ -0,0 +1,30 @@
+//go:build darwin && !cgo
+
+package commands
+
+import (
+	"github.com/go-faster/errors"
+	"github.com/spf13/cobra"
+)
+
+// The macOS menu bar integration (fyne.io/systray) is implemented in
+// Objective-C and needs cgo, so it is compiled out of CGO-disabled builds
+// (e.g. the cross-compiled release binaries). Build from source with cgo
+// enabled — the default for `go build`/`go install` on macOS — to get it.
+
+// runTray is unavailable without cgo; the menu bar integration needs the
+// Objective-C status bar bridge.
+func runTray(cmd *cobra.Command) error {
+	return errors.New(text(cmd, "tray.needs_cgo"))
+}
+
+// ensureTrayRunning is a no-op without cgo: there is no menu bar icon to spawn.
+func ensureTrayRunning(*cobra.Command) {}
+
+func installTrayAgent(cmd *cobra.Command) error {
+	return errors.New(text(cmd, "tray.needs_cgo"))
+}
+
+func uninstallTrayAgent(cmd *cobra.Command) error {
+	return errors.New(text(cmd, "tray.needs_cgo"))
+}

internal/app/commands/tray_darwin_test.go

@@ -1,4 +1,4 @@
-//go:build darwin
+//go:build darwin && cgo
 
 package commands
 

internal/app/commands/tray_icon_darwin.go

@@ -1,4 +1,4 @@
-//go:build darwin
+//go:build darwin && cgo
 
 package commands
 

internal/app/commands/tray_icon_darwin_test.go

@@ -1,4 +1,4 @@
-//go:build darwin
+//go:build darwin && cgo
 
 package commands
 

internal/app/commands/tray_launchd_darwin.go

@@ -1,4 +1,4 @@
-//go:build darwin
+//go:build darwin && cgo
 
 package commands
 

internal/app/commands/tray_lifecycle_darwin.go

@@ -1,4 +1,4 @@
-//go:build darwin
+//go:build darwin && cgo
 
 package commands
 

internal/app/localization/langs/eng.json

@@ -206,6 +206,7 @@
   "tray.short": "Run the macOS menu bar icon (timer, start last, stop)",
   "tray.disabled": "The menu bar icon is disabled. Enable it with 'tray.enabled: true' in your config (or TOCK_TRAY_ENABLED=1).",
   "tray.unsupported": "The menu bar icon is only supported on macOS.",
+  "tray.needs_cgo": "The menu bar icon needs a CGO-enabled build. The prebuilt release binaries are compiled without CGO; build from source (the default 'go build'/'go install' on macOS enables it).",
   "tray.running": "Menu bar icon started — look for the clock in the macOS menu bar (top-right). Press Ctrl-C here to quit.",
   "tray.already_running": "The menu bar icon is already running.",
   "tray.install.short": "Install a login agent so the menu bar icon always runs",