Fix recording failure in Windows PyInstaller builds with console=False

When console=False in PyInstaller builds on Windows, stdout/stderr are
not available. This causes subprocess/multiprocessing operations to fail
when they try to write output, breaking RealtimeSTT initialization.

The fix:
- Check if running as frozen executable on Windows
- Test if stdout/stderr are available (try to flush)
- If not available, redirect to io.StringIO() null streams
- This allows subprocess/multiprocessing to write without errors

This fixes the "Failed to start Recording" error that only occurred
in builds with console=False but worked fine with console=True or
when running with uv.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

main.py

@@ -10,6 +10,7 @@ optional multi-user server synchronization.
 import sys
 import multiprocessing
 from pathlib import Path
+import os
 
 # CRITICAL: Must be called before anything else with PyInstaller
 # This prevents the infinite spawning loop when the frozen executable runs
@@ -24,6 +25,21 @@ if __name__ == "__main__":
     except RuntimeError:
         pass  # Already set, ignore
 
+# Fix for Windows PyInstaller builds with console=False
+# When console is hidden, subprocess/multiprocessing can't write to stdout/stderr
+# This causes RealtimeSTT and other libraries to fail silently
+if getattr(sys, 'frozen', False) and sys.platform == 'win32':
+    # Redirect stdout/stderr to null device on Windows when frozen
+    # Only if they're not already valid (console=False builds)
+    try:
+        sys.stdout.flush()
+        sys.stderr.flush()
+    except (AttributeError, OSError):
+        # stdout/stderr are not available, redirect to null
+        import io
+        sys.stdout = io.StringIO()
+        sys.stderr = io.StringIO()
+
 # Add project root to Python path
 project_root = Path(__file__).parent
 sys.path.insert(0, str(project_root))