Utilities: add age helper for menu health label

apps/macos/Sources/Clawdis/Utilities.swift

@@ -96,6 +96,22 @@ enum LaunchAgentManager {
     }
 }
 
+// Human-friendly age string (e.g., "2m ago").
+func age(from date: Date, now: Date = .init()) -> String {
+    let seconds = max(0, Int(now.timeIntervalSince(date)))
+    let minutes = seconds / 60
+    let hours = minutes / 60
+    let days = hours / 24
+
+    if seconds < 60 { return "just now" }
+    if minutes == 1 { return "1 minute ago" }
+    if minutes < 60 { return "\(minutes)m ago" }
+    if hours == 1 { return "1 hour ago" }
+    if hours < 24 { return "\(hours)h ago" }
+    if days == 1 { return "yesterday" }
+    return "\(days)d ago"
+}
+
 @MainActor
 enum CLIInstaller {
     static func installedLocation() -> String? {