fix: stabilize aspect locked queue window resizing

Checks/compact-window.swift

@@ -472,11 +472,46 @@ struct CompactWindowChecks {
         }
     }
 
+    static func continuousQueueResize() throws {
+        let aspect = 16.0 / 9.0
+        let sidebar: CGFloat = 260
+        let window = NSWindow(contentRect: NSRect(x: -10_000, y: -10_000, width: 1_160, height: 900 / aspect),
+                              styleMask: [.titled, .resizable, .fullSizeContentView],
+                              backing: .buffered, defer: false)
+        window.isReleasedWhenClosed = false
+        defer { window.close() }
+        let controller = CompactWindowController()
+        controller.normalVideoLayout = { (aspect, sidebar) }
+        controller.attach(window)
+        for horizontal in [true, false] {
+            let start = window.frame
+            let chrome = start.height - window.contentRect(forFrameRect: start).height
+            window.delegate?.windowWillStartLiveResize?(Notification(name: NSWindow.willStartLiveResizeNotification, object: window))
+            // AppKit proposes sizes from the pointer's drag origin. The delegate's
+            // correction of the other dimension must not feed back into axis selection.
+            for offset in [CGFloat(20), 21, 22, 23, 24, 23, 22, 21, 20, 0, -1, -2] {
+                let proposal = NSSize(width: start.width + (horizontal ? offset : 0),
+                                      height: start.height + (horizontal ? 0 : offset))
+                let size = window.delegate!.windowWillResize!(window, to: proposal)
+                try require(close(horizontal ? size.width : size.height,
+                                  horizontal ? proposal.width : proposal.height),
+                            "continuous queue resize follows the dragged edge without snapping back")
+                try require(close((size.width - sidebar) / (size.height - chrome), aspect),
+                            "continuous queue resize keeps the video aspect")
+                var frame = start
+                frame.size = size
+                window.setFrame(frame, display: false)
+            }
+            window.delegate?.windowDidEndLiveResize?(Notification(name: NSWindow.didEndLiveResizeNotification, object: window))
+        }
+    }
+
     static func main() throws {
         try geometry()
         try windowBehavior()
         try reducedMotion()
         try rememberedSize()
+        try continuousQueueResize()
         print("Compact window checks passed")
     }
 }

README.md

@@ -159,7 +159,7 @@ The full suite requires a graphical macOS session and a working audio device; it
 
 The startup checks verify that playing video remains attached, unhidden and sized to its native drag surface, including with the queue open; playback-state checks alone do not establish renderer visibility.
 
-Queue-open resize checks require positive native resize increments and exercise horizontal/vertical resize-delegate proposals to preserve video aspect independently of the fixed-width sidebar. Physical edge-drag resizing still needs manual verification.
+Queue-open resize checks require positive native resize increments and exercise continuous horizontal/vertical resize-delegate sequences, including reversals, to preserve video aspect without snap-back. The driving axis is fixed for each live resize gesture so aspect corrections do not feed back into axis selection. Physical edge-drag resizing still needs manual verification.
 
 `make benchmark-playback` measures cold source startup, cached/uncached seeks, and sustained native/Cast playback with repeatable loopback fixtures. It requires the same macOS session/audio device and fixture-generation FFmpeg; results exclude live extraction, WAN/TLS, and physical-receiver latency.
 The [benchmark runner](Checks/playback-benchmark.py) accepts `--compare-native <baseline-binary>` for alternating native-only comparisons; add `--seek-work` to isolate cache-miss seeks when both binaries support that mode. Preserve the baseline executable before rebuilding.

Sources/App/CompactWindow.swift

@@ -197,6 +197,8 @@ final class CompactWindowController: NSObject {
         // NSObject forwarding returns untyped Any; accesses remain on AppKit's main thread.
         nonisolated(unsafe) weak var original: (any NSWindowDelegate)?
         private weak var owner: CompactWindowController?
+        private var resizeStartSize: NSSize?
+        private var resizeWidthDriven: Bool?
 
         init(owner: CompactWindowController, original: (any NSWindowDelegate)?) {
             self.owner = owner
@@ -212,6 +214,19 @@ final class CompactWindowController: NSObject {
             let responds = MainActor.assumeIsolated { original?.responds(to: selector) ?? false }
             return responds ? original : nil
         }
+
+        func windowWillStartLiveResize(_ notification: Notification) {
+            resizeStartSize = (notification.object as? NSWindow)?.frame.size
+            resizeWidthDriven = nil
+            original?.windowWillStartLiveResize?(notification)
+        }
+
+        func windowDidEndLiveResize(_ notification: Notification) {
+            resizeStartSize = nil
+            resizeWidthDriven = nil
+            original?.windowDidEndLiveResize?(notification)
+        }
+
         func windowWillResize(_ sender: NSWindow, to proposedSize: NSSize) -> NSSize {
             let proposed = original?.windowWillResize?(sender, to: proposedSize) ?? proposedSize
             guard let owner, !owner.isCompact, !owner.isTransitioning,
@@ -220,8 +235,16 @@ final class CompactWindowController: NSObject {
                   layout.aspect.isFinite, layout.aspect > 0 else { return proposed }
             // The sidebar stays fixed-width; only the video area is aspect-locked.
             let chrome = sender.frame.height - sender.contentRect(forFrameRect: sender.frame).height
-            let widthDriven = abs(proposed.width - sender.frame.width) >=
+            let start = resizeStartSize ?? sender.frame.size
-                abs(proposed.height - sender.frame.height) * layout.aspect
+            let widthChange = abs(proposed.width - start.width)
+            let heightChange = abs(proposed.height - start.height) * layout.aspect
+            // Latch the user's axis once. Comparing against each corrected frame
+            // makes our own aspect adjustment look like a new drag on the other axis.
+            if resizeStartSize != nil, resizeWidthDriven == nil,
+               widthChange > 0 || heightChange > 0 {
+                resizeWidthDriven = widthChange >= heightChange
+            }
+            let widthDriven = resizeWidthDriven ?? (widthChange >= heightChange)
             let minimumHeight = max(sender.minSize.height - chrome,
                                     (sender.minSize.width - layout.sidebarWidth) / layout.aspect)
             let height = max(minimumHeight, widthDriven