Record a removal's outcome, publish it, and read one directory once

The record kept only the intent, so a failed unlink read as removed; each
link now gets a synced intent and outcome line, and the outcome is the
module's link.removal event so it is not only a file on one machine.
The put-back hint no longer advises a symlink, an aliased directory is
read once, a machine-wide removal from user scope is said, and the state
directory names no owner a machine without an account cannot resolve.

modules/systemd/cmd/systemd-tools/client.go

@@ -147,6 +147,11 @@ type Manager struct {
 	// State is the module's state directory, where each removed link is recorded.
 	State string
 	Now   func() time.Time
+	// Emit publishes one of this module's events (unlink.go).
+	Emit func(eventType string, body any) error
+	// Resolve is a directory's path with every link in it followed, so one directory reached by two
+	// names is searched once (on Arch /etc/xdg/systemd/user leads to /etc/systemd/user).
+	Resolve func(path string) (string, error)
 }
 
 var userBus = regexp.MustCompile(`(?i)Failed to connect to (user scope )?bus`)