fix(cli): write machine-readable formats directly to stdout bypassing Rich line-wrapping

The format_output() function returned a string that callers passed to
Rich console.print(), which wraps long lines at terminal width.  This
injected literal newline characters into JSON string values (e.g. in
definition_of_done fields), producing invalid JSON that downstream
parsers could not decode (JSONDecodeError: Invalid control character).

For machine-readable formats (json, yaml, plain), format_output() now
writes the rendered output directly to sys.stdout and returns an empty
string.  This preserves the exact serialization from json.dumps/
yaml.dump without Rich text processing artifacts.

Refs: #746

robot/helper_project_context_cli.py

@@ -87,6 +87,31 @@ def _make_mock_container(
     return mock_container
 
 
+def _capturing_format_output(data: Any, format_type: str) -> str:
+    """Wrapper around ``format_output`` that captures stdout writes.
+
+    ``format_output`` for machine-readable formats (json, yaml, plain)
+    writes directly to ``sys.stdout`` and returns ``""``.  This wrapper
+    redirects ``sys.stdout`` only during the ``format_output`` call so
+    that the rendered content is returned as a string, allowing the
+    caller's ``console.print(result)`` to write it to the test's Rich
+    console buffer.  Structlog noise that would otherwise pollute the
+    captured stdout is excluded because the redirect is scoped tightly.
+    """
+    import sys as _sys
+
+    from cleveragents.cli.formatting import format_output as _real_format_output
+
+    buf = StringIO()
+    old = _sys.stdout
+    _sys.stdout = buf
+    try:
+        ret = _real_format_output(data, format_type)
+    finally:
+        _sys.stdout = old
+    return ret or buf.getvalue().rstrip("\n")
+
+
 def _run_cli_func(
     func: Any,
     repo: NamespacedProjectRepository,
@@ -123,6 +148,10 @@ def _run_cli_func(
             "cleveragents.cli.commands.project_context.err_console",
             test_console,
         ),
+        patch(
+            "cleveragents.cli.commands.project_context.format_output",
+            _capturing_format_output,
+        ),
     ):
         try:
             func(**kwargs)