feat(agent): unified cross-platform shell execution contract (cmd/bash)

Windows runs 'cmd.exe /d /s /c <command>' as a string command line; Linux uses ['/bin/bash', '-lc', command]. Removes implicit shell=True behavior and aligns the agent system prompt per platform.

core/llm_engine.py

@@ -37,8 +37,10 @@ from core.agent import (Agent, AgentConfig, AgentEvent, AgentMessage, AgentRunne
                         default_tools, from_openai_messages,
                         openai_stream)
 from core.agent.stream_fn import _pick_reasoning, _pick_usage
+# P0-01：配置读取统一入口（环境变量 HAOCODE_CONFIG_FILE 优先，缺省回落项目内 data/config.json）
+from core.config_paths import load_config
+from core import platform_shell  # P1-02：提示词平台段（通用正文 + 短 shell/path 段）
 
-CONFIG_PATH = os.path.join(os.path.dirname(__file__), "..", "data", "config.json")
 PROJECT_ROOT = os.path.abspath(os.path.join(os.path.dirname(__file__), ".."))
 # 🌟 Agent 系统提示词文件（项目根目录，core 前面那个 .md）
 SYSTEM_PROMPT_FILE = os.path.join(PROJECT_ROOT, "SYSTEM_PROMPT.md")
@@ -49,25 +51,25 @@ _FALLBACK_SYSTEM_PROMPT = (
 
 
 def load_system_prompt() -> str:
-    """读取 SYSTEM_PROMPT.md；缺失时用兜底短提示词。"""
+    """读取 SYSTEM_PROMPT.md；缺失时用兜底短提示词。
+
+    P1-02：通用正文 + 运行时插入的短平台 shell/path 段（占位符替换）；
+    每次请求重读本函数即重读文件，Windows 段不会出现在 Linux 请求中，反之亦然。
+    """
+    text = None
     try:
         with open(SYSTEM_PROMPT_FILE, "r", encoding="utf-8") as f:
             text = f.read().strip()
-        if text:
-            return text
     except FileNotFoundError:
         pass
-    return _FALLBACK_SYSTEM_PROMPT
+    if not text:
+        text = _FALLBACK_SYSTEM_PROMPT
+    return platform_shell.apply_platform_section(text)
 
 
 def _load_config() -> dict:
-    if os.path.exists(CONFIG_PATH):
-        try:
-            with open(CONFIG_PATH, "r", encoding="utf-8") as f:
-                return json.load(f)
-        except Exception as e:
-            print(f"[llm_engine] 读取配置失败: {e}")
-    return {}
+    """P0-01：统一走 core.config_paths.load_config（环境变量优先、容错、可见警告）。"""
+    return load_config()
 
 
 def _provider_info(config: dict, provider_name: str) -> dict: