update:1.优化 AI 流式生成和进度显示系统 2.新增写作风格系统提示词支持 3.灵感模式功能增强,支持灵感重写 4.设置页面功能扩展，新增Gemini适配器 5.提示词模板系统优化，调整灵感模式提示词

backend/app/services/ai_clients/gemini_client.py

@@ -0,0 +1,141 @@
+"""Gemini 客户端"""
+from typing import Any, AsyncGenerator, Dict, List, Optional
+import httpx
+from app.services.ai_config import AIClientConfig, default_config
+
+
+class GeminiClient:
+    """Google Gemini API 客户端"""
+
+    def __init__(self, api_key: str, base_url: Optional[str] = None, config: Optional[AIClientConfig] = None):
+        self.api_key = api_key
+        self.base_url = (base_url or "https://generativelanguage.googleapis.com/v1beta").rstrip("/")
+        self.config = config or default_config
+        http_cfg = self.config.http
+        self.client = httpx.AsyncClient(
+            timeout=httpx.Timeout(
+                connect=http_cfg.connect_timeout,
+                read=http_cfg.read_timeout,
+                write=http_cfg.write_timeout,
+                pool=http_cfg.pool_timeout
+            )
+        )
+
+    def _convert_tools_to_gemini(self, tools: list) -> list:
+        """将 OpenAI 格式工具转换为 Gemini 格式"""
+        gemini_tools = []
+        for tool in tools:
+            if tool.get("type") == "function":
+                func = tool["function"]
+                params = func.get("parameters", {}).copy() if func.get("parameters") else {}
+                params.pop("$schema", None)
+                params.pop("additionalProperties", None)
+                if params and "type" not in params:
+                    params["type"] = "object"
+                decl = {
+                    "name": func["name"],
+                    "description": func.get("description") or func["name"],
+                }
+                if params:
+                    decl["parameters"] = params
+                gemini_tools.append(decl)
+        return [{"functionDeclarations": gemini_tools}] if gemini_tools else []
+
+    async def chat_completion(
+        self,
+        messages: list,
+        model: str,
+        temperature: float,
+        max_tokens: int,
+        system_prompt: Optional[str] = None,
+        tools: Optional[list] = None,
+        tool_choice: Optional[str] = None,
+    ) -> Dict[str, Any]:
+        url = f"{self.base_url}/models/{model}:generateContent?key={self.api_key}"
+        
+        contents = []
+        for msg in messages:
+            role = "user" if msg["role"] == "user" else "model"
+            contents.append({"role": role, "parts": [{"text": msg["content"]}]})
+        
+        payload = {
+            "contents": contents,
+            "generationConfig": {"temperature": temperature, "maxOutputTokens": max_tokens}
+        }
+        if system_prompt:
+            payload["systemInstruction"] = {"parts": [{"text": system_prompt}]}
+        if tools:
+            payload["tools"] = self._convert_tools_to_gemini(tools)
+
+        response = await self.client.post(url, json=payload)
+        response.raise_for_status()
+        data = response.json()
+        
+        candidates = data.get("candidates", [])
+        if not candidates or len(candidates) == 0:
+            # 返回空内容而不是报错，保持流程继续
+            return {
+                "content": "",
+                "tool_calls": None,
+                "finish_reason": "stop"
+            }
+        
+        parts = candidates[0].get("content", {}).get("parts", [])
+        text = ""
+        tool_calls = []
+        
+        for part in parts:
+            if "text" in part:
+                text += part["text"]
+            elif "functionCall" in part:
+                fc = part["functionCall"]
+                tool_calls.append({
+                    "id": f"call_{fc['name']}",
+                    "type": "function",
+                    "function": {"name": fc["name"], "arguments": fc.get("args", {})}
+                })
+        
+        return {
+            "content": text,
+            "tool_calls": tool_calls if tool_calls else None,
+            "finish_reason": "tool_calls" if tool_calls else "stop"
+        }
+
+    async def chat_completion_stream(
+        self,
+        messages: list,
+        model: str,
+        temperature: float,
+        max_tokens: int,
+        system_prompt: Optional[str] = None,
+    ) -> AsyncGenerator[str, None]:
+        url = f"{self.base_url}/models/{model}:streamGenerateContent?key={self.api_key}&alt=sse"
+        
+        contents = []
+        for msg in messages:
+            role = "user" if msg["role"] == "user" else "model"
+            contents.append({"role": role, "parts": [{"text": msg["content"]}]})
+        
+        payload = {
+            "contents": contents,
+            "generationConfig": {"temperature": temperature, "maxOutputTokens": max_tokens}
+        }
+        if system_prompt:
+            payload["systemInstruction"] = {"parts": [{"text": system_prompt}]}
+
+        async with self.client.stream("POST", url, json=payload) as response:
+            response.raise_for_status()
+            async for line in response.aiter_lines():
+                if line.startswith("data: "):
+                    import json
+                    try:
+                        data = json.loads(line[6:])
+                        candidates = data.get("candidates", [])
+                        if candidates and len(candidates) > 0:
+                            parts = candidates[0].get("content", {}).get("parts", [])
+                            if parts and len(parts) > 0:
+                                text = parts[0].get("text", "")
+                                if text:
+                                    yield text
+                    except:
+                        continue