refactor(settings): 移动配置文件读写及默认常量至settings模块

- 将默认模型和基础URL常量移至settings模块，统一管理
- 实现用户配置和项目配置的读取、写入接口
- 提供获取用户和项目配置路径的工具函数
- 清理ui/utils中的相关冗余代码，简化代码结构
- 统一类型引用，调整session、session-types、settings和common之间的导入路径
- 移除AsciiArt模块内容，清理无用代码

Author: hqwlkj

Screenshot_2026-05-23_195028.png

@@ -1,7 +1,7 @@
 import React from "react";
 import { render } from "ink";
 import { setShellIfWindows } from "./common/shell-utils";
-import { checkForNpmUpdate, promptForPendingUpdate, type PackageInfo } from "./updateCheck";
+import { checkForNpmUpdate, promptForPendingUpdate, type PackageInfo } from "./common/updateCheck";
 import { AppContainer } from "./ui";
 
 const args = process.argv.slice(2);

docs/issue_0522.md

@@ -3,7 +3,7 @@ import * as os from "os";
 import * as path from "path";
 import OpenAI from "openai";
 import { Agent, fetch as undiciFetch } from "undici";
-import { resolveCurrentSettings } from "../ui";
+import { resolveCurrentSettings } from "../settings";
 
 // Custom undici Agent with a 180-second keepAlive timeout.  The default
 // global fetch (undici) only keeps connections alive for 4 seconds, which

src/cli.tsx

@@ -5,8 +5,8 @@ import * as os from "os";
 import * as path from "path";
 import { render, type Instance } from "ink";
 import chalk from "chalk";
-import { UpdatePrompt, type UpdatePromptChoice } from "./ui";
-import { killProcessTree } from "./common/process-tree";
+import { UpdatePrompt, type UpdatePromptChoice } from "../ui";
+import { killProcessTree } from "./process-tree";
 
 export type PackageInfo = {
   name: string;

src/common/openai-client.ts

@@ -4,7 +4,7 @@ import * as os from "os";
 import * as path from "path";
 import { fileURLToPath } from "url";
 import ejs from "ejs";
-import type { SessionMessage } from "./session";
+import type { SessionMessage } from "./session-types";
 import { findGitBashPath, resolveShellPath } from "./common/shell-utils";
 import { supportsMultimodal } from "./common/model-capabilities";
 
@@ -166,8 +166,7 @@ function getCurrentDateAndModelPrompt(model?: string): string {
 
 export function getSystemPrompt(_projectRoot: string, options: PromptToolOptions = {}): string {
   const toolDocs = readToolDocs(getExtensionRoot(), options);
-  const basePrompt = toolDocs ? `${SYSTEM_PROMPT_BASE}\n\n# Available Tools\n\n${toolDocs}` : SYSTEM_PROMPT_BASE;
-  return basePrompt;
+  return toolDocs ? `${SYSTEM_PROMPT_BASE}\n\n# Available Tools\n\n${toolDocs}` : SYSTEM_PROMPT_BASE;
 }
 
 export function getCompactPrompt(sessionMessages: SessionMessage[]): string {