[Security] Address critical host-shell escape in LocalSandboxProvider (#1547)

* fix(security): disable host bash by default in local sandbox

* fix(security): address review feedback for local bash hardening

* fix(ci): sort live test imports for lint

* style: apply backend formatter

---------

Co-authored-by: Willem Jiang <willem.jiang@gmail.com>

backend/tests/test_subagent_prompt_security.py

@@ -0,0 +1,41 @@
+"""Tests for subagent availability and prompt exposure under local bash hardening."""
+
+from deerflow.agents.lead_agent import prompt as prompt_module
+from deerflow.subagents import registry as registry_module
+
+
+def test_get_available_subagent_names_hides_bash_when_host_bash_disabled(monkeypatch) -> None:
+    monkeypatch.setattr(registry_module, "is_host_bash_allowed", lambda: False)
+
+    names = registry_module.get_available_subagent_names()
+
+    assert names == ["general-purpose"]
+
+
+def test_get_available_subagent_names_keeps_bash_when_allowed(monkeypatch) -> None:
+    monkeypatch.setattr(registry_module, "is_host_bash_allowed", lambda: True)
+
+    names = registry_module.get_available_subagent_names()
+
+    assert names == ["general-purpose", "bash"]
+
+
+def test_build_subagent_section_hides_bash_examples_when_unavailable(monkeypatch) -> None:
+    monkeypatch.setattr(prompt_module, "get_available_subagent_names", lambda: ["general-purpose"])
+
+    section = prompt_module._build_subagent_section(3)
+
+    assert "Not available in the current sandbox configuration" in section
+    assert 'bash("npm test")' not in section
+    assert 'read_file("/mnt/user-data/workspace/README.md")' in section
+    assert "available tools (ls, read_file, web_search, etc.)" in section
+
+
+def test_build_subagent_section_includes_bash_when_available(monkeypatch) -> None:
+    monkeypatch.setattr(prompt_module, "get_available_subagent_names", lambda: ["general-purpose", "bash"])
+
+    section = prompt_module._build_subagent_section(3)
+
+    assert "For command execution (git, build, test, deploy operations)" in section
+    assert 'bash("npm test")' in section
+    assert "available tools (bash, ls, read_file, web_search, etc.)" in section