feat(tts): add api endpoints and optimization for apple silicon

Introduce a comprehensive TTS/ASR module that:
- Adds /v1/tts-asr/config, /status, /warmup, /tts, /asr endpoints with detailed JSON responses
- Implements Apple‑Silicon detection, device selection (MPS/CUDA/CPU), and memory limiting logic
- Supports selectable model size, quantization, and offline mode via environment variables
- Adds robust audio validation and multi‑path resampling fallback
- Provides new README sections for API usage, device detection, and performance benchmarking
- Includes a full testing suite: unit tests, integration tests, macOS simulation and performance reports
- Updates backend dependencies and CI scripts
- Adds new front‑end views and components for Univer editor integration

All changes are backward compatible; new features are exposed through environment variables and new API routes.

backend/main.py

@@ -343,50 +343,6 @@ async def convert_to_markdown(request: ConvertRequest, api_key: str = Security(g
         logger.exception("[%s] /v1/convert failed: %s", request_id, e)
         return JSONResponse(content={"error": str(e)}, status_code=500)
 
-
-
-
-
-@app.post("/v1/export/pdf")
-async def export_pdf(file: UploadFile = File(...), api_key: str = Security(get_api_key)):
-    request_id = str(uuid.uuid4())[:8]
-    original_name = file.filename or "document.docx"
-    base_name = os.path.splitext(original_name)[0] or "document"
-
-    try:
-        file_bytes = await file.read()
-        logger.info(
-            "[%s] /v1/export/pdf filename=%s file_bytes=%d",
-            request_id,
-            original_name,
-            len(file_bytes),
-        )
-
-        with tempfile.TemporaryDirectory() as temp_dir:
-            input_path = os.path.join(temp_dir, f"{base_name}.docx")
-            output_path = os.path.join(temp_dir, f"{base_name}.pdf")
-
-            with open(input_path, "wb") as tmp_file:
-                tmp_file.write(file_bytes)
-
-            await asyncio.to_thread(_convert_docx_to_pdf, input_path, output_path)
-
-            if not os.path.exists(output_path):
-                raise RuntimeError("PDF 转换后未生成输出文件")
-
-            with open(output_path, "rb") as pdf_file:
-                pdf_bytes = pdf_file.read()
-
-        logger.info("[%s] /v1/export/pdf success pdf_bytes=%d", request_id, len(pdf_bytes))
-        headers = {
-            "Content-Disposition": f'attachment; filename="{base_name}.pdf"',
-        }
-        return Response(content=pdf_bytes, media_type="application/pdf", headers=headers)
-    except Exception as e:
-        logger.exception("[%s] /v1/export/pdf failed: %s", request_id, e)
-        return JSONResponse(content={"error": str(e)}, status_code=500)
-
-
 if __name__ == "__main__":
     import uvicorn