refactor: 删除 config.json + 内置工具抽离 + 统一接口

删除:
  - config.rs / config.json（AppConfig/LmStudioConfig）
  - LM Studio 残留（lmstudio.rs 已在之前删除）
  - main.rs 中散落的内置工具 match arms

新增:
  - src/tools/builtin.rs — BuiltinRegistry 统一切入
    get_current_datetime、manage_memos 为核心内置工具
    统一参数校验、风险等级、错误返回

改动:
  - 模型名直接从 DEEPSEEK_MODEL 环境变量读取
  - builtin 工具与 skills 工具统一经过 SkillRegistry 审批
  - query_capabilities 合并内置 + 外部技能列表

src/main.rs

@@ -1,5 +1,4 @@
 mod cli;
-mod config;
 mod context;
 mod db;
 mod llm;
@@ -12,7 +11,6 @@ mod wechat;
 
 use clap::Parser;
 use cli::{Cli, Commands, SkillsAction};
-use config::AppConfig;
 use context::MemoryStore;
 use db::Database;
 use llm::{Conversation, ConversationConfig, DEFAULT_SYSTEM_PROMPT, ToolExecutor, Usage};
@@ -44,9 +42,7 @@ async fn main() {
         }
     }
 
-    let config = AppConfig::from_file("config.json");
-
-    // 初始化数据库（如果配置了 DATABASE_URL）
+    let file_state = state::StateManager::new(".data/weixin-ilink");
     let database = match Database::connect().await {
         Ok(db) => {
             info!("✅ 数据库连接成功");
@@ -65,7 +61,7 @@ async fn main() {
     memory_store.load("").await;
 
     // 文件状态管理器（降级方案）
-    let file_state = state::StateManager::new(&config.storage.state_dir);
+    let file_state = state::StateManager::new(".data/weixin-ilink");
 
     match cli.command {
         Commands::Login { timeout } => {
@@ -75,15 +71,7 @@ async fn main() {
             llm: enable_llm,
             echo,
         } => {
-            cmd_listen(
-                enable_llm,
-                echo,
-                &database,
-                &file_state,
-                &config,
-                &memory_store,
-            )
-            .await;
+            cmd_listen(enable_llm, echo, &database, &file_state, &memory_store).await;
         }
         Commands::Send {
             to,
@@ -103,7 +91,7 @@ async fn main() {
             cmd_usage(&database, since, until, model).await;
         }
         Commands::Service => {
-            cmd_listen(true, false, &database, &file_state, &config, &memory_store).await
+            cmd_listen(true, false, &database, &file_state, &memory_store).await
         }
         Commands::Skills { action } => {
             cmd_skills(action).await;
@@ -162,7 +150,6 @@ async fn cmd_listen(
     echo: bool,
     database: &Option<Arc<Database>>,
     file_state: &state::StateManager,
-    config: &AppConfig,
     memory_store: &Arc<MemoryStore>,
 ) {
     // 从数据库或文件加载认证
@@ -230,7 +217,7 @@ async fn cmd_listen(
     let conversation = if enable_llm {
         let sys_prompt = std::env::var("WEIXIN_LLM_SYSTEM_PROMPT")
             .unwrap_or_else(|_| DEFAULT_SYSTEM_PROMPT.to_string());
-        let model = config.llm.deepseek.model.clone();
+        let model = std::env::var("DEEPSEEK_MODEL").unwrap_or_else(|_| "deepseek-v4-flash".to_string());
 
         let mut cfg = ConversationConfig {
             system_prompt: sys_prompt,
@@ -355,6 +342,12 @@ async fn cmd_listen(
 
             Box::pin(async move {
                 let user_id = session.lock().await.current_user_id.clone();
+
+                // 内置工具优先
+                if let Some(result) = tools::builtin::BuiltinRegistry::execute(&n, &args).await {
+                    return Ok(result.output);
+                }
+
                 match n.as_str() {
                     "read_memories" => return Ok(memory_store.read_for(&user_id).await),
                     "write_memory" => {
@@ -369,15 +362,12 @@ async fn cmd_listen(
                     "read_summaries" => return Ok(context::tools::read_summaries(&session).await),
                     "query_capabilities" => {
                         if let Some(r) = reg.as_ref() {
-                            return Ok(build_capability_list(r));
+                            let mut specs: Vec<tools::skill::SkillSpec> = r.list_specs().into_iter().cloned().collect();
+                            specs.extend(tools::builtin::BuiltinRegistry::specs());
+                            return Ok(build_capability_list(&specs));
                         }
                         return Ok("暂无工具".to_string());
                     }
-                    "get_current_datetime" => {
-                        let now = chrono::Local::now();
-                        return Ok(serde_json::json!({"datetime": now.format("%Y-%m-%d %H:%M:%S").to_string()}).to_string());
-                    }
-                    "manage_memos" => return handle_memos(&args).await,
                     "call_capability" => {
                         let cap_params: serde_json::Value = serde_json::from_str(&args).unwrap_or_default();
                         let cap_name = cap_params.get("name").and_then(|v| v.as_str()).map(|s| s.to_string());
@@ -818,9 +808,9 @@ fn global_skills_dir() -> std::path::PathBuf {
         .join("skills")
 }
 
-fn build_capability_list(reg: &SkillRegistry) -> String {
+fn build_capability_list(specs: &[tools::skill::SkillSpec]) -> String {
     let mut lines = vec!["📋 可用工具:".to_string()];
-    for spec in reg.list_specs() {
+    for spec in specs {
         let risk = if spec.risk_level == tools::skill::RiskLevel::High { " ⚠️需确认" } else { "" };
         lines.push(format!(
             "\n🔹 {} {} — {}", spec.name, risk, spec.description
@@ -829,44 +819,6 @@ fn build_capability_list(reg: &SkillRegistry) -> String {
     lines.join("\n")
 }
 
-async fn handle_memos(args_json: &str) -> Result<String, String> {
-    use std::io::{Read, Write};
-    let params: serde_json::Value = serde_json::from_str(args_json).unwrap_or_default();
-    let action = params.get("action").and_then(|v| v.as_str()).unwrap_or("list");
-    let path = ".data/memos.json";
-    std::fs::create_dir_all(".data").ok();
-
-    let mut data: Vec<serde_json::Value> = if std::path::Path::new(path).exists() {
-        serde_json::from_str(&std::fs::read_to_string(path).unwrap_or_default()).unwrap_or_default()
-    } else {
-        vec![]
-    };
-
-    match action {
-        "add" => {
-            let content = params.get("content").and_then(|v| v.as_str()).unwrap_or("");
-            if content.is_empty() { return Ok(r#"{"error":"请提供 content 参数"}"#.to_string()); }
-            let next_id = data.iter().filter_map(|m| m.get("id").and_then(|v| v.as_i64())).max().unwrap_or(0) + 1;
-            data.push(serde_json::json!({"id": next_id, "content": content, "created_at": chrono::Local::now().format("%Y-%m-%d %H:%M").to_string()}));
-            std::fs::write(path, serde_json::to_string_pretty(&data).unwrap()).ok();
-            Ok(format!("已添加备忘录 #{}", next_id))
-        }
-        "list" => {
-            if data.is_empty() { return Ok("暂无备忘录".to_string()); }
-            Ok(data.iter().map(|m| format!("#{} [{}] {}", m["id"], m.get("created_at").and_then(|v| v.as_str()).unwrap_or("?"), m["content"].as_str().unwrap_or("?"))).collect::<Vec<_>>().join("\n"))
-        }
-        "delete" => {
-            let id = params.get("id").and_then(|v| v.as_i64()).unwrap_or(0);
-            let before = data.len();
-            data.retain(|m| m.get("id").and_then(|v| v.as_i64()) != Some(id));
-            if data.len() == before { return Ok(format!("未找到备忘录 #{}", id)); }
-            std::fs::write(path, serde_json::to_string_pretty(&data).unwrap()).ok();
-            Ok(format!("已删除备忘录 #{}", id))
-        }
-        _ => Ok("未知操作，支持: add, list, delete".to_string())
-    }
-}
-
 async fn cmd_skills(action: SkillsAction) {
     use dialoguer::{MultiSelect, theme::ColorfulTheme};
     use console::Term;