Better modularize clipboard code (add "clip" package; break up TOTP code

clip/launchClipClearProcessGUIGeneric.go

@@ -0,0 +1,10 @@
+//go:build (windows || darwin || android || ios || termux || wsl) && interactive
+
+package clip
+
+// LaunchClipClearProcess launches the timed clipboard clearing process.
+// For interactive GUI/TUI implementations, the clipboard clearing process is launched as a goroutine.
+// copySubject can be omitted to clear the clipboard immediately and unconditionally.
+func LaunchClipClearProcess(copySubject string) {
+	go clipClearProcess(copySubject)
+}