Fix infinite spawn loop on all platforms with PyInstaller

Extended the freeze_support fix to work on Linux and macOS, not just Windows.
The spawn loop can occur on any platform when PyInstaller bundles apps that
use multiprocessing.

Changes:
- Removed Windows-only condition for freeze_support()
- Added multiprocessing.set_start_method('spawn', force=True)
- Set spawn method for consistency across all platforms
- Prevents fork-related issues on Linux with PyInstaller

Why this is needed:
- PyTorch, faster-whisper, and RealtimeSTT all use multiprocessing
- PyInstaller frozen executables need explicit spawn method configuration
- Linux defaults to 'fork' which can cause issues with frozen executables
- 'spawn' method is more reliable with PyInstaller on all platforms

This ensures the app launches only once on Windows, Linux, and macOS.

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

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

main.py

@@ -11,11 +11,19 @@ import sys
 import multiprocessing
 from pathlib import Path
 
-# CRITICAL: Must be called before anything else on Windows with PyInstaller
+# CRITICAL: Must be called before anything else with PyInstaller
 # This prevents the infinite spawning loop when the frozen executable runs
-if sys.platform == 'win32':
+# Required on all platforms (Windows, Linux, macOS) when using multiprocessing
 multiprocessing.freeze_support()
 
+# Set multiprocessing start method to 'spawn' for consistency across platforms
+# This prevents issues with PyInstaller frozen executables
+if __name__ == "__main__":
+    try:
+        multiprocessing.set_start_method('spawn', force=True)
+    except RuntimeError:
+        pass  # Already set, ignore
+
 # Add project root to Python path
 project_root = Path(__file__).parent
 sys.path.insert(0, str(project_root))