fix(macos): use safe FileHandle reads

apps/macos/Sources/ClawdisCLI/BrowserCLI.swift

@@ -263,7 +263,7 @@ enum BrowserCLI {
             return try String(contentsOfFile: jsFile, encoding: .utf8)
         }
         if options.jsStdin {
-            let data = FileHandle.standardInput.readDataToEndOfFile()
+            let data = FileHandle.standardInput.readToEndSafely()
             return String(data: data, encoding: .utf8) ?? ""
         }
         if let js = options.js, !js.isEmpty {

apps/macos/Sources/ClawdisCLI/FileHandle+SafeRead.swift

@@ -0,0 +1,25 @@
+import Foundation
+
+extension FileHandle {
+    /// Reads until EOF using the throwing FileHandle API and returns empty `Data` on failure.
+    ///
+    /// Important: Avoid legacy, non-throwing FileHandle read APIs (e.g. `readDataToEndOfFile()` and
+    /// `availableData`). They can raise Objective-C exceptions when the handle is closed/invalid, which
+    /// will abort the process.
+    func readToEndSafely() -> Data {
+        do {
+            return try self.readToEnd() ?? Data()
+        } catch {
+            return Data()
+        }
+    }
+
+    /// Reads up to `count` bytes using the throwing FileHandle API and returns empty `Data` on failure/EOF.
+    func readSafely(upToCount count: Int) -> Data {
+        do {
+            return try self.read(upToCount: count) ?? Data()
+        } catch {
+            return Data()
+        }
+    }
+}