Fix comprehensive memory leaks (adapted from PR dwarvesf#335)

Adds the non-overlapping pieces of huynguyenh's PR dwarvesf#335 on top of
rm335's PR dwarvesf#346. Handles the biggest leak source (NSLayoutConstraint
retention when NSImageViews were recreated 9-10 times per toggle).

- Deactivate NSLayoutConstraints before removing views in
  NSStackView.removeAllSubViews (prevents constraint retention of
  removed NSImageViews — primary leak source on macOS Sequoia/Tahoe)
- Extend StatusBarController.deinit to invalidate timer and remove
  the always-hidden NSStatusItem
- Change toggleStatusBarIfNeeded to only create the always-hidden
  status item when it doesn't already exist, instead of tearing down
  and recreating on every .alwayHideToggle notification

Combined with the widest-display collapse-length calc in dwarvesf#354 and the
bounded-length work in dwarvesf#344, this should resolve the runaway memory
growth reported in upstream dwarvesf#326, dwarvesf#336, dwarvesf#351, dwarvesf#352.

Co-Authored-By: huynguyenh <hoanghuy2908@gmail.com>

Author: sdenike

hidden/Extensions/StackView+Extension.swift

@@ -11,6 +11,7 @@ import Cocoa
 extension NSStackView {
     func removeAllSubViews() {
         for view in self.views {
+            NSLayoutConstraint.deactivate(view.constraints)
             view.removeFromSuperview()
         }
     }

hidden/Features/StatusBar/StatusBarController.swift

@@ -77,6 +77,11 @@ class StatusBarController {
 
     deinit {
         NotificationCenter.default.removeObserver(self)
+        timer?.invalidate()
+        timer = nil
+        if let statusItem = self.btnAlwaysHidden {
+            NSStatusBar.system.removeStatusItem(statusItem)
+        }
     }
 
     @objc private func handleScreenParametersChanged() {
@@ -269,20 +274,19 @@ extension StatusBarController {
     }
     @objc private func toggleStatusBarIfNeeded() {
         updateCollapsedLengths()
-        
+
         if Preferences.alwaysHiddenSectionEnabled {
-            if let existing = self.btnAlwaysHidden {
-                NSStatusBar.system.removeStatusItem(existing)
-            }
-            self.btnAlwaysHidden = NSStatusBar.system.statusItem(withLength: btnAlwaysHiddenLength)
-            if let button = btnAlwaysHidden?.button {
-                button.image = self.imgIconLine
-                button.appearsDisabled = true
+            if self.btnAlwaysHidden == nil {
+                self.btnAlwaysHidden = NSStatusBar.system.statusItem(withLength: btnAlwaysHiddenLength)
+                if let button = btnAlwaysHidden?.button {
+                    button.image = self.imgIconLine
+                    button.appearsDisabled = true
+                }
+                self.btnAlwaysHidden?.autosaveName = "hiddenbar_terminate"
             }
-            self.btnAlwaysHidden?.autosaveName = "hiddenbar_terminate"
         } else {
-            if let existing = self.btnAlwaysHidden {
-                NSStatusBar.system.removeStatusItem(existing)
+            if let statusItem = self.btnAlwaysHidden {
+                NSStatusBar.system.removeStatusItem(statusItem)
             }
             self.btnAlwaysHidden = nil
         }