Fix LuxTTS + Chatterbox in prod: bundle espeak/perth data, fix multiprocessing

- collect-all piper_phonemize to bundle espeak-ng-data for LuxTTS phonemization
- Set ESPEAK_DATA_PATH in frozen builds so the C library finds bundled data
- collect-all perth to bundle pretrained watermark model for Chatterbox
- Add multiprocessing.freeze_support() to fix resource_tracker subprocess crash

backend/build_binary.py

@@ -111,6 +111,12 @@ def build_server(cuda=False):
         # inflect uses typeguard @typechecked which calls inspect.getsource()
         # at import time — needs .py source files, not just .pyc bytecode
         '--collect-all', 'inflect',
+        # perth ships pretrained watermark model files (hparams.yaml, .pth.tar)
+        # in perth/perth_net/pretrained/ — needed by chatterbox at runtime
+        '--collect-all', 'perth',
+        # piper_phonemize ships espeak-ng-data/ (phoneme tables, language dicts)
+        # needed by LuxTTS for text-to-phoneme conversion
+        '--collect-all', 'piper_phonemize',
     ])
 
     # Add CUDA-specific hidden imports

backend/server.py

@@ -26,6 +26,20 @@ if not _is_writable(sys.stdout):
 if not _is_writable(sys.stderr):
     sys.stderr = open(os.devnull, 'w')
 
+# PyInstaller + multiprocessing: child processes re-execute the frozen binary
+# with internal arguments. freeze_support() handles this and exits early.
+import multiprocessing
+multiprocessing.freeze_support()
+
+# In frozen builds, piper_phonemize's espeak-ng C library falls back to
+# /usr/share/espeak-ng-data/ which doesn't exist.  Point it at the bundled
+# data directory instead.
+if getattr(sys, 'frozen', False):
+    _meipass = getattr(sys, '_MEIPASS', os.path.dirname(sys.executable))
+    _espeak_data = os.path.join(_meipass, 'piper_phonemize', 'espeak-ng-data')
+    if os.path.isdir(_espeak_data):
+        os.environ.setdefault('ESPEAK_DATA_PATH', _espeak_data)
+
 # Fast path: handle --version before any heavy imports so the Rust
 # version check doesn't block for 30+ seconds loading torch etc.
 if "--version" in sys.argv: