Give the remaining tray applets their modules, each with one start

openrazer (the official driver, daemon and library), polychromatic (the
AUR tray, kept as found; its i3 line moves out of the i3 module into its
own node-display-session contribution), forticlient (the AUR VPN client:
its service declared, its configuration never read) and nm-applet (the
desktop half of NetworkManager, apart from the server-side module).

The openrazer daemon fails on both workstations because the account is
not in the openrazer group; openrazer_check names it and the README
carries the one-off step, since the account's user resource is zsh's.

desktop.go learns to tell a program from another sharing its 15-character
command name, so polychromatic's tools never count or end themselves, and
a copies test holds the six carriers to one text.

modules/nextcloud-client/cmd/nextcloud-client-tools/copies_test.go

@@ -0,0 +1,37 @@
+package main
+
+// The desktop applications whose bundles carry desktop.go. Each builds alone, so each has its own copy;
+// this test, itself one of the copied files, holds them to one text wherever the siblings are present.
+
+import (
+	"bytes"
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+var carriers = []string{"blueman", "forticlient", "nextcloud-client", "nm-applet", "openrazer", "polychromatic", "slack"}
+
+func TestEveryDesktopApplicationCarriesTheSameCopy(t *testing.T) {
+	compared := 0
+	for _, module := range carriers {
+		dir := filepath.Join("..", "..", "..", module, "cmd", module+"-tools")
+		if _, err := os.Stat(dir); err != nil {
+			continue
+		}
+		for _, f := range []string{"desktop.go", "desktop_test.go", "copies_test.go"} {
+			mine, err := os.ReadFile(f)
+			if err != nil {
+				t.Fatal(err)
+			}
+			theirs, err := os.ReadFile(filepath.Join(dir, f))
+			if err != nil || !bytes.Equal(mine, theirs) {
+				t.Errorf("%s's copy of %s differs from this one: change every copy together", module, f)
+			}
+		}
+		compared++
+	}
+	if compared == 0 {
+		t.Log("no sibling copies beside this module")
+	}
+}