Fix false positive overlap detection for half/third actions

Origin-only matching caused false positives when a larger window
(e.g. maximized) shared the same origin as the target position.
Now requires that the other window fits within the candidate's
dimensions - origins must match AND the other window must be the
same size or smaller. This prevents a maximized window from
triggering the offset on a left-half placement, while still
detecting a quarter behind an eighth at the same grid position.

Fixes #1762 post-merge bug reported by maintainer.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: MyronKoch

Rectangle/WindowManager.swift

@@ -228,8 +228,11 @@ class WindowManager {
             let candidateAX = candidate.screenFlipped
             let hasOverlap = otherWindows.contains { element in
                 let otherFrame = element.frame
-                return abs(otherFrame.origin.x - candidateAX.origin.x) < tolerance
+                let originsMatch = abs(otherFrame.origin.x - candidateAX.origin.x) < tolerance
                     && abs(otherFrame.origin.y - candidateAX.origin.y) < tolerance
+                let otherFitsInCandidate = otherFrame.width <= candidateAX.width + tolerance
+                    && otherFrame.height <= candidateAX.height + tolerance
+                return originsMatch && otherFitsInCandidate
             }
 
             guard hasOverlap else { break }