Add LLVM installation and exclude unnecessary modules from PyInstaller build

- Install llvm-dev on Ubuntu for llvmlite compilation
- Install LLVM via Homebrew on macOS and configure PATH
- Exclude matplotlib, IPython, notebook, pytest, tensorboard from bundle to reduce size
- Keep --onefile mode with module exclusions to avoid 4GB limit

backend/build_binary.py

@@ -26,6 +26,18 @@ def build_server():
         args.extend(['--paths', str(local_qwen_path)])
         print(f"Using local qwen_tts source from: {local_qwen_path}")
 
+    # Exclude unnecessary modules to reduce size
+    args.extend([
+        '--exclude-module', 'matplotlib',
+        '--exclude-module', 'IPython',
+        '--exclude-module', 'notebook',
+        '--exclude-module', 'pytest',
+        '--exclude-module', 'setuptools',
+        '--exclude-module', 'torch.distributions',
+        '--exclude-module', 'torch.testing',
+        '--exclude-module', 'tensorboard',
+    ])
+
     # Add hidden imports
     args.extend([
         '--hidden-import', 'backend',