Initial commit: audio-chat with fixes

- Created AGENTS.md with architecture documentation
- Fixed race conditions and async patterns
- Added conversation history to LLM prompts
- Fixed TTS audio shape handling
- Added buffer limits and graceful shutdown
- Fixed client.py with file sending support
- Removed duplicate requirements
- Added .gitignore

engine/stt.py

@@ -0,0 +1,49 @@
+from faster_whisper import WhisperModel
+from config import Config
+import io
+import numpy as np
+
+
+class STTEngine:
+    def __init__(self):
+        self.model = None
+        self.config = Config()
+        self._model_size = self._resolve_model_size(self.config.STT_MODEL)
+
+    def _resolve_model_size(self, model_name: str) -> str:
+        """Extract model size from various naming conventions."""
+        # Handle Systran/faster-whisper-* format
+        if "faster-whisper-" in model_name:
+            return model_name.split("faster-whisper-")[-1]
+        # Handle whisper-* format
+        if model_name.startswith("whisper-"):
+            return model_name[len("whisper-"):]
+        # Return as-is for direct model names
+        return model_name
+
+    def initialize(self):
+        device = "cuda" if self.config.DEVICE == "auto" else self.config.DEVICE
+        self.model = WhisperModel(
+            self._model_size,
+            device=device,
+            compute_type="float16" if device == "cuda" else "int8",
+            download_root=None,
+        )
+
+    def transcribe(self, audio_bytes: bytes) -> str:
+        if not self.model:
+            self.initialize()
+
+        audio_file = io.BytesIO(audio_bytes)
+        segments, info = self.model.transcribe(
+            audio_file,
+            beam_size=5,
+            language="ru",
+            vad_filter=True,
+        )
+
+        text = ""
+        for segment in segments:
+            text += segment.text + " "
+
+        return text.strip()