feat(macos): hover HUD for activity

apps/macos/Sources/Clawdis/WindowPlacement.swift

@@ -42,6 +42,28 @@ enum WindowPlacement {
         return NSRect(x: x, y: y, width: clampedWidth, height: clampedHeight)
     }
 
+    static func anchoredBelowFrame(size: NSSize, anchor: NSRect, padding: CGFloat, in bounds: NSRect) -> NSRect {
+        if bounds == .zero {
+            let x = round(anchor.midX - size.width / 2)
+            let y = round(anchor.minY - size.height - padding)
+            return NSRect(x: x, y: y, width: size.width, height: size.height)
+        }
+
+        let clampedWidth = min(size.width, bounds.width)
+        let clampedHeight = min(size.height, bounds.height)
+
+        let desiredX = round(anchor.midX - clampedWidth / 2)
+        let desiredY = round(anchor.minY - clampedHeight - padding)
+
+        let maxX = bounds.maxX - clampedWidth
+        let maxY = bounds.maxY - clampedHeight
+
+        let x = maxX >= bounds.minX ? min(max(desiredX, bounds.minX), maxX) : bounds.minX
+        let y = maxY >= bounds.minY ? min(max(desiredY, bounds.minY), maxY) : bounds.minY
+
+        return NSRect(x: x, y: y, width: clampedWidth, height: clampedHeight)
+    }
+
     static func ensureOnScreen(
         window: NSWindow,
         defaultSize: NSSize,