docs: remove duplicate YAML example and fix comments

- Simplify YAML preset example by removing redundant content
- Remove "optional" wording from pgvector extension comment

Author: liut

README.md

@@ -128,15 +128,11 @@ forego run go run . web
 ### Prepare preset data file in YAML
 
 ```yaml
-# Simple preset
 welcome: "Hello, I am your virtual assistant. How can I help you?"
 systemPrompt: "You are a helpful assistant."
 toolsPrompt: "You will select the appropriate tool based on the user's question and call the tool to solve the problem."
 
 # Or with custom tool descriptions
-welcome: "Hello, I am your virtual assistant. How can I help you?"
-systemPrompt: "You are a helpful assistant."
-toolsPrompt: "You will select the appropriate tool based on the user's question and call the tool to solve the problem."
 tools:
   kb_search: "Search documents in knowledge base with subject. When faced with unknown or uncertain issues, prioritize consulting the knowledge base."
   kb_create: "Create new document of knowledge base, all parameters are required. Note: Unless the user explicitly requests supplementary content, do not invoke it."
@@ -165,7 +161,7 @@ GRANT ALL PRIVILEGES ON DATABASE morign to morign;
 
 \c morign
 
--- optional: install extension from https://github.com/pgvector/pgvector
+-- install extension from https://github.com/pgvector/pgvector
 CREATE EXTENSION vector;
 
 ```

README_CN.md

@@ -128,15 +128,11 @@ forego run go run . web
 ### 准备 YAML 预设数据文件
 
 ```yaml
-# 简单配置
 welcome: "你好，我是你的虚拟助手。有什么可以帮助你的吗？"
 systemPrompt: "你是一位有用的助手。"
 toolsPrompt: "根据用户问题选择合适的工具并调用来解决问题。"
 
 # 或配置自定义工具描述
-welcome: "你好，我是你的虚拟助手。有什么可以帮助你的吗？"
-systemPrompt: "你是一位有用的助手。"
-toolsPrompt: "根据用户的问题选择合适的工具，区分读写操作，提取必要参数进行调用，使用中文关键词进行搜索，必要时翻译英文内容。"
 tools:
   kb_search: "在知识库中搜索相关内容。当遇到未知或不确定的问题时，优先查阅知识库。"
   kb_create: "创建新的知识库文档，所有参数必填。注意：除非用户明确要求补充内容，否则不要调用。"
@@ -165,7 +161,7 @@ GRANT ALL PRIVILEGES ON DATABASE morign to morign;
 
 \c morign
 
-# 可选：安装扩展 https://github.com/pgvector/pgvector
+# 安装扩展 https://github.com/pgvector/pgvector
 CREATE EXTENSION vector;
 
 ```