fix: handle nil Finder selection on macOS 15+

On macOS 15+, `finder.selection?.get()` via ScriptingBridge returns nil
when nothing is selected (older macOS returned an empty array). The old
`guard let selection, let selectionItems = selection.get() else throw`
misread this as a permission failure, so every click with no selection
surfaced `OITError.cannotAccessFinder` and fell out of `openOutsideSandbox`
silently — the lite binary only writes the error to `~/Library/Logs` and
exits, giving the user no feedback.

Treat nil as an empty selection and fall through to the front-window
check. Also unify the singular and plural helpers on the safer
`as? [FinderItem]` cast (dropping an unsound `as! FinderItem` on
individual items in the singular variant).

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

Author: oaeen

OpenInTerminalCore/FinderManager.swift

@@ -17,17 +17,18 @@ public class FinderManager {
     public func getFullUrlToFrontFinderWindowOrSelectedFile() throws -> URL? {
 
         let finder = SBApplication(bundleIdentifier: Constants.Id.Finder)! as FinderApplication
-        
+
         var target: FinderItem
-        
-        guard let selection = finder.selection,
-            let selectionItems = selection.get() else {
-                throw OITError.cannotAccessFinder
-        }
-        
-        if let firstItem = (selectionItems as! Array<AnyObject>).first {
+
+        // On macOS 15+, finder.selection?.get() returns nil when nothing is
+        // selected (older macOS returned an empty array). Treat nil as "no
+        // selection" and fall through to the front-window check, instead of
+        // throwing cannotAccessFinder which surfaces no UI feedback.
+        let selectionItems = (finder.selection?.get() as? [FinderItem]) ?? []
+
+        if let firstItem = selectionItems.first {
             // Files or folders selected
-            target = firstItem as! FinderItem
+            target = firstItem
         } else {
             // Check if there are finder windows opened
             guard let windows = finder.FinderWindows?(),
@@ -59,18 +60,17 @@ public class FinderManager {
     public func getFullUrlsToFrontFinderWindowOrSelectedFile() throws -> [URL] {
 
         let finder = SBApplication(bundleIdentifier: Constants.Id.Finder)! as FinderApplication
-        
+
         var targets: [FinderItem]
-        
-        guard let selection = finder.selection,
-            let selectionItems = selection.get() else {
-                throw OITError.cannotAccessFinder
-        }
-        
-        if let items = selectionItems as? Array<FinderItem>,
-            items.count > 0 {
+
+        // See note in getFullUrlToFrontFinderWindowOrSelectedFile: on macOS
+        // 15+ a nil result from selection.get() means "nothing selected",
+        // not a permission failure. Treat it as empty and fall through.
+        let selectionItems = (finder.selection?.get() as? [FinderItem]) ?? []
+
+        if !selectionItems.isEmpty {
             // Files or folders are selected
-            targets = items
+            targets = selectionItems
         } else {
             // Check if there are opened finder windows
             guard let windows = finder.FinderWindows?(),