Fix test runner output capture and Linux build error

- test-examples.pl: add pump() calls around SIGINT in keep-alive tests so
  IPC::Run drains the stdout pipe; without pumping $out stays empty causing
  ApplicationEnd and ContextAware to fail in interpreter mode
- RunCommand.swift: guard setvbuf(stdout) with #if canImport(Darwin) to fix
  Swift 6 strict concurrency error on Linux where stdout is a mutable C global
  rather than a macro; FileHandle.standardOutput.write() bypasses C stdio
  buffering on Linux anyway

Author: KrisSimon

Sources/AROCLI/Commands/RunCommand.swift

@@ -100,7 +100,12 @@ struct RunCommand: AsyncParsableCommand {
         // Force unbuffered stdout so every print() reaches the pipe immediately.
         // Without this, Swift fully-buffers stdout when piped (e.g. during tests),
         // causing observer/event output to be lost until the process exits.
+        // On Linux, stdout is a mutable C global (not a macro) which Swift 6's concurrency
+        // checker flags as unsafe. FileHandle.standardOutput.write() bypasses C stdio
+        // buffering on Linux anyway, so we only need setvbuf on Darwin.
+        #if canImport(Darwin)
         setvbuf(stdout, nil, _IONBF, 0)
+        #endif
 
         var mutableSelf = self
         mutableSelf.extractRunCommandFlags()

test-examples.pl

@@ -857,10 +857,14 @@ sub run_console_example_internal {
     if ($keep_alive) {
         # Wait for the application to start, then send SIGINT for graceful shutdown
         sleep 1;
+        # Drain stdout/stderr pipe before sending SIGINT
+        eval { pump $handle while $handle->pumpable && length($out) == 0 };
         say "  Sending SIGINT for graceful shutdown" if $options{verbose};
         eval { $handle->signal('INT'); };
         # Allow time for Application-End handler to execute and flush output
         sleep 1;
+        # Drain remaining output after SIGINT
+        eval { pump $handle while $handle->pumpable };
     }
 
     eval {
@@ -938,10 +942,14 @@ sub run_debug_example {
     if ($keep_alive) {
         # Wait for the application to start, then send SIGINT for graceful shutdown
         sleep 1;
+        # Drain stdout/stderr pipe before sending SIGINT
+        eval { pump $handle while $handle->pumpable && length($out) == 0 };
         say "  Sending SIGINT for graceful shutdown" if $options{verbose};
         eval { $handle->signal('INT'); };
         # Allow time for Application-End handler to execute and flush output
         sleep 1;
+        # Drain remaining output after SIGINT
+        eval { pump $handle while $handle->pumpable };
     }
 
     eval {