fix(cli): fix JSON validation and step definition bugs in ACMS context CLI tests

- Fix step_output_valid_json to check context.last_command_output first
  (ACMS path) before falling back to context.result envelope validation,
  resolving JSON validation failure in context list --format json scenario
- Fix step_json_entries_with_values to parse context.last_command_output
  when context.json_output is not set, fixing the last integration scenario
- Move import json as _json from inside function bodies to module level
  in context.py for cleaner style (reviewer suggestion)

ISSUES CLOSED: #9585

features/steps/acms_context_list_add_cli_steps.py

@@ -693,6 +693,16 @@ def step_output_files_added_count(context: Context, count: int) -> None:
 @then("the JSON output should contain entries with:")
 def step_json_entries_with_values(context: Context) -> None:
     """Verify JSON entries contain specific values."""
+    import json as _json
+
+    if not hasattr(context, "json_output"):
+        raw = getattr(context, "last_command_output", "")
+        try:
+            context.json_output = _json.loads(raw)
+        except (_json.JSONDecodeError, ValueError) as e:
+            raise AssertionError(
+                f"Output is not valid JSON: {e}\nOutput: {raw}"
+            ) from e
     entries = context.json_output.get("entries", context.json_output)
     for row in context.table:
         field = row["field"]

features/steps/cli_output_formats_steps.py

@@ -239,16 +239,19 @@ def step_save_yaml_keys(context: Context) -> None:
 def step_output_valid_json(context: Context) -> None:
     # Support both context.result (CLI output format tests) and
     # context.last_command_output (ACMS context CLI tests)
-    if not hasattr(context, "result"):
-        # ACMS context CLI test path
-        raw = getattr(context, "last_command_output", "")
+    last_cmd_output = getattr(context, "last_command_output", "")
+    if last_cmd_output:
+        # ACMS context CLI test path: last_command_output takes priority
         try:
-            context.json_output = json.loads(raw)
+            context.json_output = json.loads(last_cmd_output)
         except json.JSONDecodeError as e:
             raise AssertionError(
-                f"Output is not valid JSON: {e}\nOutput: {raw}"
+                f"Output is not valid JSON: {e}\nOutput: {last_cmd_output}"
             ) from e
         return
+    if not hasattr(context, "result"):
+        # No output captured at all
+        raise AssertionError("No CLI output captured in context")
     assert context.result.exit_code == 0, (
         f"CLI exited with {context.result.exit_code}: {context.result.output}"
     )

src/cleveragents/cli/commands/context.py

@@ -9,6 +9,7 @@ Deprecated alias: ``agents context <subcommand>`` (emits deprecation warning)
 
 from __future__ import annotations
 
+import json as _json
 from pathlib import Path
 from typing import TYPE_CHECKING, Annotated, Any
 
@@ -243,8 +244,6 @@ def context_add(
     Context files are the source files that the AI will read and understand
     when creating or modifying code.
     """
-    import json as _json
-
     from cleveragents.application.container import get_container
     from cleveragents.application.services.context_service import ContextService
     from cleveragents.application.services.project_service import ProjectService
@@ -449,8 +448,6 @@ def context_list(
 
     Or list named contexts in a directory.
     """
-    import json as _json
-
     if context_dir is not None:
         # List named contexts in the given directory
         ctx_base = context_dir