W22: coverage metric + network tests + Tool stream feedback + stdin pipe + session path + dependency check (W22.1-W22.6)

- W22.1: gcovr 覆盖率度量 + CI coverage job（40% 阈值 warning）
- W22.2: network_plugin 单元测试（parse_headers_json/extract_host_port/SSE/异常保护）
- W22.3: Tool Calling 流式反馈（chat_stream + "[工具调用]/[工具结果]" 状态行）
- W22.4: --prompt stdin pipe（--prompt - 从 stdin 读取）
- W22.5: session 路径健壮化（static 缓存 + mkdir + fallback）
- W22.6: 插件依赖拓扑静态校验（validate_dependencies 循环/缺失检测）

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

dstalk-cli/src/main.cpp

@@ -406,9 +406,16 @@ int main(int argc, char* argv[])
         for (int i = 1; i < argc; ++i) {
             if (std::strcmp(argv[i], "--batch") == 0) {
                 batch_mode = true;
-            } else if (std::strcmp(argv[i], "--prompt") == 0 && i + 1 < argc && argv[i+1][0] != '-') {
-                prompt_arg = argv[++i];
+            } else if (std::strcmp(argv[i], "--prompt") == 0) {
                 batch_mode = true;
+                if (i + 1 < argc && argv[i+1][0] != '-') {
+                    prompt_arg = argv[++i];
+                } else if (i + 1 < argc && std::strcmp(argv[i+1], "-") == 0) {
+                    ++i;
+                    prompt_arg = "-";  // stdin sentinel
+                } else {
+                    prompt_arg = "-";  // --prompt without value → read stdin
+                }
             }
         }
     }
@@ -524,10 +531,25 @@ int main(int argc, char* argv[])
 
     // ---- --prompt 批处理模式 (非交互) ----
     if (prompt_arg) {
-        if (prompt_arg[0] == '\0') {
-            std::fprintf(stderr, "empty prompt\n");
-            dstalk_shutdown();
-            return EXIT_FATAL;
+        std::string prompt_text;
+        if (std::strcmp(prompt_arg, "-") == 0) {
+            // --prompt - or --prompt (no arg): read prompt from stdin
+            char buf[4096];
+            while (std::fgets(buf, sizeof(buf), stdin)) {
+                prompt_text += buf;
+            }
+            if (prompt_text.empty()) {
+                std::fprintf(stderr, "empty prompt\n");
+                dstalk_shutdown();
+                return EXIT_FATAL;
+            }
+        } else {
+            if (prompt_arg[0] == '\0') {
+                std::fprintf(stderr, "empty prompt\n");
+                dstalk_shutdown();
+                return EXIT_FATAL;
+            }
+            prompt_text = prompt_arg;
         }
         if (!g_ai || !g_session) {
             std::fprintf(stderr, CLR_RED "[ERROR] AI or session service unavailable\n" CLR_RESET);
@@ -536,7 +558,7 @@ int main(int argc, char* argv[])
         }
         int history_count = 0;
         const dstalk_message_t* history = g_session->history(&history_count);
-        dstalk_chat_result_t result = g_ai->chat(history, history_count, prompt_arg, nullptr);
+        dstalk_chat_result_t result = g_ai->chat(history, history_count, prompt_text.c_str(), nullptr);
         if (result.ok) {
             std::printf("%s\n", result.content ? result.content : "");
             g_ai->free_result(&result);
@@ -654,8 +676,10 @@ int main(int argc, char* argv[])
                         ? boost::json::value_to<std::string>(*id_j) : "";
 
                     // 执行工具
+                    std::printf(CLR_DIM "[工具调用] %s...\n" CLR_RESET, tool_name.c_str());
                     char* exec_result = g_tools->execute(tool_name.c_str(), tool_args.c_str());
                     if (exec_result) {
+                        std::printf(CLR_DIM "[工具结果] ok\n" CLR_RESET);
                         dstalk_message_t tool_msg = {
                             "tool",
                             exec_result,
@@ -666,6 +690,7 @@ int main(int argc, char* argv[])
                         dstalk_free(exec_result);
                         any_executed = true;
                     } else {
+                        std::printf(CLR_DIM "[工具结果] fail\n" CLR_RESET);
                         // 单工具失败：log + skip
                         std::fprintf(stderr, CLR_YELLOW "[WARN] tool '%s' returned null, skipping\n" CLR_RESET,
                                      tool_name.c_str());
@@ -674,20 +699,16 @@ int main(int argc, char* argv[])
 
                 if (!any_executed) break;
 
-                // 重新调用 AI（chat 非流式，此时 history 已包含工具结果）
+                // 重新调用 AI（chat_stream 流式，此时 history 已包含工具结果）
                 history_count = 0;
                 history = g_session->history(&history_count);
-                char* tools_json = g_tools->get_tools_json();
 
                 g_ai->free_result(&result);
-                result = g_ai->chat(history, history_count, nullptr, tools_json);
-
-                if (tools_json) dstalk_free(tools_json);
+                bool tool_stream_first = true;
+                result = g_ai->chat_stream(history, history_count, nullptr, on_stream_token, &tool_stream_first);
 
                 if (result.ok) {
-                    if (result.content && result.content[0]) {
-                        std::printf("%s\n", result.content);
-                    }
+                    std::printf(CLR_RESET "\n");
                     dstalk_message_t ai_followup = {
                         "assistant",
                         result.content,