feat: switch to systemd-journal-logger, add debug logging (v0.6.0)

Replace env_logger with systemd-journal-logger for consistent logging
across moonset/moonlock/moongreet. Add MOONSET_DEBUG env var and debug
statements across all modules. Also includes shared blur cache for
multi-monitor and detached moonlock spawn for lock action.

src/users.rs

@@ -55,6 +55,7 @@ pub fn get_avatar_path_with(
     // ~/.face takes priority
     let face = home.join(".face");
     if face.exists() {
+        log::debug!("Avatar: using ~/.face");
         return Some(face);
     }
 
@@ -63,6 +64,7 @@ pub fn get_avatar_path_with(
         if accountsservice_dir.exists() {
             let icon = accountsservice_dir.join(name);
             if icon.exists() {
+                log::debug!("Avatar: using AccountsService icon");
                 return Some(icon);
             }
         }