fix(backend): update test_read_builtin_blocked for workspace-scoped Read

Read is now workspace-scoped (allowed within sdk_cwd, denied outside).
Split the old test into two: test_read_within_workspace_allowed and
test_read_outside_workspace_blocked.

autogpt_platform/backend/backend/copilot/sdk/security_hooks_test.py

@@ -56,11 +56,19 @@ def test_unknown_tool_allowed():
 # -- Workspace-scoped tools --------------------------------------------------
 
 
-def test_read_builtin_blocked():
-    """SDK built-in Read is blocked — all reads go through MCP read_file tool."""
+def test_read_within_workspace_allowed():
+    """Read is workspace-scoped — allowed within sdk_cwd for tool-results."""
     result = _validate_tool_access(
         "Read", {"file_path": f"{SDK_CWD}/file.txt"}, sdk_cwd=SDK_CWD
     )
+    assert result == {}
+
+
+def test_read_outside_workspace_blocked():
+    """Read outside the workspace is denied."""
+    result = _validate_tool_access(
+        "Read", {"file_path": "/etc/passwd"}, sdk_cwd=SDK_CWD
+    )
     assert _is_denied(result)