improve log window: monospace, scrollbar, smarter autoscroll

Monospaced font and semantic colors (dark-mode correct), visible
vertical scroller (was missing), text inset, centered window with a
proper title. Autoscroll now only follows the tail when already at the
bottom instead of yanking the scroll position on every log line.

Also sets isReleasedWhenClosed = false, fixing a latent crash on
close-then-reopen (the settings window already had this guard).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

BrewBar/LogWindowController.swift

@@ -14,22 +14,41 @@ class LogWindowController: NSWindowController {
 
         self.init(window: window)
 
-        window.title = "Logs"
+        window.title = "BrewBar Logs"
+        // the controller keeps the window alive; without this, closing the
+        // window would deallocate it and reopening would crash
+        window.isReleasedWhenClosed = false
+        window.center()
 
         let scrollView = NSScrollView(frame: window.contentView!.bounds)
         scrollView.autoresizingMask = [.width, .height]
+        scrollView.hasVerticalScroller = true
 
         textView = NSTextView(frame: scrollView.bounds)
         textView.isEditable = false
         textView.autoresizingMask = [.width, .height]
+        textView.font = .monospacedSystemFont(ofSize: 12, weight: .regular)
+        textView.textColor = .textColor // adapts to light/dark mode
+        textView.backgroundColor = .textBackgroundColor
+        textView.textContainerInset = NSSize(width: 8, height: 8)
 
         scrollView.documentView = textView
         window.contentView?.addSubview(scrollView)
     }
 
     func update(text: String) {
+        // only follow the tail if the user is already at the bottom — don't
+        // yank the scroll position away while they are reading older output
+        let wasAtBottom: Bool = if let scrollView = textView.enclosingScrollView {
+            scrollView.contentView.bounds.maxY >= textView.frame.height - 30
+        } else {
+            true
+        }
+
         textView.string = text
 
+        if wasAtBottom {
             textView.scrollToEndOfDocument(nil)
         }
     }
+}