fix: AgentConfig.bot_id 用 project_dir_key 覆盖，使 workspace 按用户隔离

deep_assistant/prompt_loader 用 config.bot_id 拼 projects/robot/{bot_id}，
之前只改 project_dir 无效。from_v3_request 在 bot_config 带 project_dir_key 时
用它覆盖 bot_id，使 workspace、系统提示词路径、skills 目录都按用户隔离。
普通 bot 不返回 project_dir_key，行为不变。

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

agent/agent_config.py

@@ -308,8 +308,12 @@ class AgentConfig:
         enable_thinking = bot_config.get("enable_thinking", False)
         enable_memori = bot_config.get("enable_memori", False)
 
+        # 通用智能体按用户隔离：用 project_dir_key 覆盖 bot_id，
+        # 使 workspace / system_prompt 路径 / skills 目录都落到 projects/robot/{bot_id}-{user}
+        effective_bot_id = bot_config.get("project_dir_key") or request.bot_id
+
         config = cls(
-            bot_id=request.bot_id,
+            bot_id=effective_bot_id,
             api_key=bot_config.get("api_key", ""),
             model_name=bot_config.get("model", "qwen/qwen3-next-80b-a3b-instruct"),
             model_server=bot_config.get("model_server", ""),