feat: 新增 stardomain 沙箱子项目脚手架（Docker + Rust 过滤层）

提供统一沙箱运行时，支持 local/sandbox 两种模式切换。Rust 层负责命令和代码的策略过滤，
Docker 层负责实际的进程隔离。包含三种预设策略：agent_exec / tool_run / untrusted。

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

subprojects/stardomain/src/sandbox/config.rs

@@ -0,0 +1,34 @@
+/*
+ * Copyright 2026 zhaoxi826
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ */
+
+pub struct SandboxConfig {
+    pub mode: SandboxMode,
+    pub workspace: String,
+    pub timeout_secs: u64,
+    pub memory_limit_mb: u64,
+    pub policy_name: String,
+}
+
+pub enum SandboxMode {
+    Local,
+    Sandbox,
+}
+
+impl Default for SandboxConfig {
+    fn default() -> Self {
+        SandboxConfig {
+            mode: SandboxMode::Sandbox,
+            workspace: "/tmp/stardomain_ws".to_string(),
+            timeout_secs: 30,
+            memory_limit_mb: 512,
+            policy_name: "agent_exec".to_string(),
+        }
+    }
+}

subprojects/stardomain/src/sandbox/executor.rs

@@ -0,0 +1,23 @@
+/*
+ * Copyright 2026 zhaoxi826
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ */
+
+/// Executor: responsible for running commands either locally or in Docker.
+/// This is a stub — actual Docker execution will be implemented later.
+pub struct Executor;
+
+impl Executor {
+    pub fn run_local(_command: &str) -> (String, String, i32) {
+        ("".to_string(), "".to_string(), 0)
+    }
+
+    pub fn run_docker(_command: &str) -> (String, String, i32) {
+        ("".to_string(), "[stardomain] Docker execution not yet implemented".to_string(), 1)
+    }
+}

subprojects/stardomain/src/sandbox/mod.rs

@@ -0,0 +1,38 @@
+/*
+ * Copyright 2026 zhaoxi826
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ */
+
+pub mod config;
+pub mod executor;
+
+use pyo3::prelude::*;
+
+#[pyclass]
+#[derive(Clone)]
+pub struct SandboxResult {
+    #[pyo3(get)]
+    pub stdout: String,
+    #[pyo3(get)]
+    pub stderr: String,
+    #[pyo3(get)]
+    pub exit_code: i32,
+    #[pyo3(get)]
+    pub killed_by_timeout: bool,
+}
+
+impl SandboxResult {
+    pub fn stub(input: &str) -> Self {
+        SandboxResult {
+            stdout: format!("[stardomain stub] would execute: {}", input),
+            stderr: String::new(),
+            exit_code: 0,
+            killed_by_timeout: false,
+        }
+    }
+}