Add metadata validation script and module documentation

- Introduced a new Python script `check_agents_metadata.py` for validating agent metadata, including YAML parsing, rating ranges, and cross-references.
- Added usage instructions and exit codes for the script.
- Created a new markdown file `模块目录和功能说明.md` to outline the directory structure and functionality of the modules.
- Added a text file `说明此文件不可AI修改.txt` to specify that certain files should not be modified by AI, including important information about the `dstalk` framework and its modules.

plugins/session/src/session_plugin.cpp

@@ -1,6 +1,13 @@
-// plugin-session: 会话管理服务插件
-// 提供 dstalk_session_service_t vtable 实现
-// 依赖: file_io (save/load 需要文件操作)
+/*
+ * @file session_plugin.cpp
+ * @brief Session plugin: conversation message history management with save/load.
+ * 会话插件：对话消息历史管理，支持保存/加载。
+ * Copyright (c) 2026 dstalk contributors. GPLv3.
+ */
+
+// plugin-session: 会话管理服务插件 / Session management service plugin
+// 提供 dstalk_session_service_t vtable 实现 / Provides dstalk_session_service_t vtable implementation
+// 依赖: file_io (save/load 需要文件操作) / Depends on: file_io (save/load needs file operations)
 #include "dstalk/dstalk_host.h"
 #include "dstalk/dstalk_types.h"
 #include "dstalk/dstalk_services.h"
@@ -24,14 +31,14 @@
 namespace json = boost::json;
 
 // ============================================================
-// 内部 C++ 数据结构
+// 内部 C++ 数据结构 / Internal C++ data structures
 // ============================================================
 
-// W14.3: g_host / g_file_io 使用 atomic 指针，写入 acquire/release，读取无锁
+// W14.3: g_host / g_file_io 使用 atomic 指针，写入 acquire/release，读取无锁 / g_host / g_file_io use atomic pointers, write with acquire/release, read lock-free
 static std::atomic<const dstalk_host_api_t*> g_host{nullptr};
 static std::atomic<const dstalk_file_io_service_t*> g_file_io{nullptr};
 
-// 内部消息结构（C++ 易用，外部暴露 C struct）
+// 内部消息结构（C++ 易用，外部暴露 C struct） / Internal message struct (C++ friendly, externally exposed as C struct)
 struct InternalMessage {
     std::string role;
     std::string content;
@@ -39,21 +46,24 @@ struct InternalMessage {
     std::string tool_calls_json;
 };
 
-// 会话历史 + 缓存 —— W14.3: mutex 保护读写
+// 会话历史 + 缓存 —— W14.3: mutex 保护读写 / Session history + cache — W14.3: mutex protects read/write
 static std::vector<InternalMessage> g_history;
 static std::vector<dstalk_message_t> g_cached_history;
 static std::mutex g_session_mutex;
 
 // ============================================================
-// Token 计数工具（内联，避免硬依赖 context 头文件）
+// Token 计数工具（内联，避免硬依赖 context 头文件） / Token counting utilities (inline, avoids hard dep on context headers)
 // ============================================================
 
+// 如果字节是 ASCII (0x00–0x7F) 则返回 true / Returns true if the byte is ASCII (0x00–0x7F).
 static bool is_ascii(unsigned char c) { return c < 0x80; }
 
+// 启发式判断：如果字节起始一个 UTF-8 CJK 统一表意文字 (0xE4–0xE9) 则返回 true / Heuristic: returns true if the byte starts a CJK Unified Ideograph in UTF-8 (0xE4–0xE9).
 static bool starts_cjk(unsigned char c) {
     return c >= 0xE4 && c <= 0xE9;
 }
 
+// 使用启发式 UTF-8 字节计数估算单条消息的 token 数 / Estimate token count for a single message using heuristic UTF-8 byte counting.
 static size_t count_tokens_one(const std::string& text) {
     size_t ascii_chars   = 0;
     size_t chinese_chars = 0;
@@ -85,9 +95,10 @@ static size_t count_tokens_one(const std::string& text) {
     }
 
     size_t content_tokens = (ascii_chars / 4) + (chinese_chars / 2) + (other_chars / 3);
-    return content_tokens + 4; // +4 per message overhead
+    return content_tokens + 4; // +4 每条消息开销 / +4 per message overhead
 }
 
+// 估算所有消息的总 token 数 / Estimate total token count across all messages.
 static size_t count_tokens_all(const std::vector<InternalMessage>& msgs) {
     size_t total = 0;
     for (const auto& m : msgs) {
@@ -97,13 +108,15 @@ static size_t count_tokens_all(const std::vector<InternalMessage>& msgs) {
 }
 
 // ============================================================
-// 辅助：刷新 C 缓存数组（调用方需持有 g_session_mutex）
+// 辅助：刷新 C 缓存数组（调用方需持有 g_session_mutex） / Helper: rebuild C cached array (caller must hold g_session_mutex)
 // ============================================================
 
+// 从内部消息 vector 重建 C 兼容的缓存历史数组。调用方必须持有 g_session_mutex / Rebuild the C-compatible cached history array from the internal message vector.
+// Caller must hold g_session_mutex.
 static void rebuild_cached_history_locked() {
     const dstalk_host_api_t* host = g_host.load(std::memory_order_acquire);
 
-    // 释放旧的字符串
+    // 释放旧的字符串 / Free old strings
     for (auto& m : g_cached_history) {
         if (m.role)           { host->free(const_cast<char*>(m.role)); }
         if (m.content)        { host->free(const_cast<char*>(m.content)); }
@@ -112,7 +125,7 @@ static void rebuild_cached_history_locked() {
     }
     g_cached_history.clear();
 
-    // 重建
+    // 重建 / Rebuild
     g_cached_history.reserve(g_history.size());
     for (const auto& im : g_history) {
         dstalk_message_t cm;
@@ -125,9 +138,10 @@ static void rebuild_cached_history_locked() {
 }
 
 // ============================================================
-// Session 服务 vtable 实现 (W14.3: try/catch + mutex)
+// Session 服务 vtable 实现 (W14.3: try/catch + mutex) / Session service vtable implementation (W14.3: try/catch + mutex)
 // ============================================================
 
+// 向对话历史追加一条消息 / Append a message to the conversation history.
 static void session_add(const dstalk_message_t* msg) {
     try {
         if (!msg) return;
@@ -148,11 +162,13 @@ static void session_add(const dstalk_message_t* msg) {
     }
 }
 
+// 清空对话历史中的所有消息 / Clear all messages from the conversation history.
 static void session_clear() {
     std::lock_guard<std::mutex> lock(g_session_mutex);
     g_history.clear();
 }
 
+// 将当前对话历史序列化为 JSON 行文件并保存到 path / Serialize the current conversation history to a JSON lines file at `path`.
 static int session_save(const char* path) {
     try {
         if (!path) return -1;
@@ -187,6 +203,7 @@ static int session_save(const char* path) {
     }
 }
 
+// 从 JSON 行文件中加载对话历史，替换当前历史 / Load conversation history from a JSON lines file at `path`, replacing current history.
 static int session_load(const char* path) {
     try {
         if (!path) return -1;
@@ -246,6 +263,7 @@ static int session_load(const char* path) {
     }
 }
 
+// 返回指向缓存 C 消息数组的指针，并将 *out_count 设置为数组大小 / Return a pointer to the cached C-array of messages and set *out_count to its size.
 static const dstalk_message_t* session_history(int* out_count) {
     try {
         std::lock_guard<std::mutex> lock(g_session_mutex);
@@ -265,6 +283,7 @@ static const dstalk_message_t* session_history(int* out_count) {
     }
 }
 
+// 返回当前对话历史的估算 token 数 / Return the estimated token count for the current conversation history.
 static int session_token_count() {
     try {
         std::lock_guard<std::mutex> lock(g_session_mutex);
@@ -290,11 +309,12 @@ static dstalk_session_service_t g_session_service = {
 };
 
 // ============================================================
-// W20.6: 默认会话保存路径（平台标准目录）
+// W20.6: 默认会话保存路径（平台标准目录） / Default session save path (platform standard directory)
 // ============================================================
 
+// 返回平台特定的默认会话保存路径，根据需要创建目录 / Return the platform-specific default session save path, creating directories as needed.
 static std::string get_default_session_path() {
-    // W22.5: static 缓存 + mkdir 保障 + 失败 fallback 到当前目录
+    // W22.5: static 缓存 + mkdir 保障 + 失败 fallback 到当前目录 / static cache + mkdir guarantee + fallback to current dir on failure
     static std::string cached_path = []() -> std::string {
 #ifdef _WIN32
         char* buf = nullptr;
@@ -323,14 +343,17 @@ static std::string get_default_session_path() {
 }
 
 // ============================================================
-// 插件生命周期
+// 插件生命周期 / Plugin lifecycle
 // ============================================================
 
+// 插件初始化：保存主机指针，查询 file_io 依赖，注册 session 服务，
+// 并从默认路径自动加载已有会话 / Plugin init: store host pointer, query file_io dependency, register session service,
+// and auto-load any existing session from the default path.
 static int on_init(const dstalk_host_api_t* host) {
     try {
         g_host.store(host, std::memory_order_release);
 
-        // 查询依赖服务: file_io
+        // 查询依赖服务: file_io / Query dependency service: file_io
         void* raw = host->query_service("file_io", 1);
         if (!raw) {
             host->log(DSTALK_LOG_ERROR, "[plugin-session] required service 'file_io' not found");
@@ -338,11 +361,11 @@ static int on_init(const dstalk_host_api_t* host) {
         }
         g_file_io.store(static_cast<const dstalk_file_io_service_t*>(raw), std::memory_order_release);
 
-        // 注册自身服务
+        // 注册自身服务 / Register own service
         int ret = host->register_service("session", 1, &g_session_service);
         if (ret != 0) return ret;
 
-        // W20.6: 从默认路径恢复会话（文件不存在则静默失败）
+        // W20.6: 从默认路径恢复会话（文件不存在则静默失败） / Restore session from default path (silent fail if file missing)
         session_load(get_default_session_path().c_str());
 
         return 0;
@@ -357,10 +380,13 @@ static int on_init(const dstalk_host_api_t* host) {
     }
 }
 
+// 插件关闭：自动保存会话到默认路径，失败时回退到当前目录，
+// 然后释放缓存历史和清空状态 / Plugin shutdown: auto-save session to default path, fallback to current dir on failure,
+// then release cached history and clear state.
 static void on_shutdown() {
     try {
-        // W20.6: 清空前自动保存到默认路径
-        // W21.4: 失败告警 + 当前目录 fallback
+        // W20.6: 清空前自动保存到默认路径 / Auto-save to default path before clearing
+        // W21.4: 失败告警 + 当前目录 fallback / Failure warning + current dir fallback
         int ret = session_save(get_default_session_path().c_str());
         if (ret != 0) {
             const dstalk_host_api_t* h = g_host.load(std::memory_order_acquire);
@@ -389,7 +415,7 @@ static void on_shutdown() {
 static dstalk_plugin_info_t g_info = {
     "session",
     "1.0.0",
-    "Session management plugin with save/load support",
+    "Session management plugin with save/load support    / 支持保存/加载的会话管理插件",
     DSTALK_API_VERSION,
     {"file_io", nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr},
     on_init,
@@ -397,6 +423,7 @@ static dstalk_plugin_info_t g_info = {
     nullptr
 };
 
+// 必须入口点：返回插件描述符给主机 / Mandatory entry point: returns the plugin descriptor to the host.
 extern "C" DSTALK_PLUGIN_EXPORT dstalk_plugin_info_t* dstalk_plugin_init(void) {
     return &g_info;
 }