fix: 移除app.py中的直接模型加载代码

- 删除旧的测试代码中的直接模型实例化
- 模型加载现在通过TravelAssistant类管理
- 修复启动时的认证错误

app.py

@@ -1,45 +1,39 @@
-from transformers import AutoProcessor, Gemma3nForConditionalGeneration
-from PIL import Image
-import requests
-import torch
-
-model_id = "google/gemma-3n-e2b-it"
-
-model = Gemma3nForConditionalGeneration.from_pretrained(model_id, device="cuda", torch_dtype=torch.bfloat16,).eval()
-
-processor = AutoProcessor.from_pretrained(model_id)
-
-messages = [
-    {
-        "role": "system",
-        "content": [{"type": "text", "text": "You are a helpful assistant."}]
-    },
-    {
-        "role": "user",
-        "content": [
-            {"type": "image", "image": "https://huggingface.co/datasets/huggingface/documentation-images/resolve/main/bee.jpg"},
-            {"type": "text", "text": "Describe this image in detail."}
-        ]
-    }
-]
-
-inputs = processor.apply_chat_template(
-    messages,
-    add_generation_prompt=True,
-    tokenize=True,
-    return_dict=True,
-    return_tensors="pt",
-).to(model.device, dtype=torch.bfloat16)
-
-input_len = inputs["input_ids"].shape[-1]
-
-with torch.inference_mode():
-    generation = model.generate(**inputs, max_new_tokens=100, do_sample=False)
-    generation = generation[0][input_len:]
-
-decoded = processor.decode(generation, skip_special_tokens=True)
-print(decoded)
-
-# **Overall Impression:** The image is a close-up shot of a vibrant garden scene,
-# focusing on a cluster of pink cosmos flowers and a busy bumblebee.
-# It has a slightly soft, natural feel, likely captured in daylight.
+# app.py - 正确的版本
+from fastapi import FastAPI, HTTPException
+from fastapi.middleware.cors import CORSMiddleware
+from fastapi.responses import JSONResponse
+from utils.validators import ChatRequest, ChatResponse
+from utils.logger import log
+from modules.travel_assistant import TravelAssistant
+import traceback
+
+# --- FastAPI 应用设置 ---
+app = FastAPI(
+    title="Modular Travel Assistant API",
+    description="一个采用模块化和分层架构的旅行助手API",
+    version="2.0.0",
+    docs_url="/docs",
+    redoc_url="/redoc"
+)
+
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=["*"],
+    allow_credentials=True,
+    allow_methods=["*"],
+    allow_headers=["*"],
+)
+
+# --- 全局服务实例 ---
+try:
+    log.info("🔄 开始初始化 Travel Assistant 服务...")
+    assistant = TravelAssistant()  # 这里才是正确的模型加载方式
+    SERVICE_READY = True
+    log.info("🚀 FastAPI 应用启动成功，服务已就绪。")
+except Exception as e:
+    assistant = None
+    SERVICE_READY = False
+    log.critical(f"💥 FATAL: 服务初始化失败: {e}")
+    log.critical(f"💥 错误详情: {traceback.format_exc()}")
+
+# ... 其余的API端点代码