fix(approval): surface pending-approval state with explicit marker visible to LLM

When a tool call requires user approval in the non-blocking gateway path,
the LLM previously received a result that was indistinguishable from a
failed tool call (exit_code=-1, error=message). The LLM could not tell
whether the tool was pending approval, had returned empty results, or had
failed silently — causing it to burn context on wrong hypotheses.

Fix changes the result format to include:
- status: pending_approval (clear state name)
- approval_pending: True (explicit boolean for LLMs to detect)
- error: cleared to empty string (removes misleading error signal)

This lets the LLM reason about approval latency vs actual errors,
short-circuiting the previous silent failure mode.

Fixes #14806

tools/approval.py

@@ -1332,7 +1332,8 @@ def check_all_command_guards(command: str, env_type: str,
         return {
             "approved": False,
             "pattern_key": primary_key,
-            "status": "approval_required",
+            "status": "pending_approval",
+            "approval_pending": True,
             "command": command,
             "description": combined_desc,
             "message": (

tools/terminal_tool.py

@@ -1863,12 +1863,13 @@ def terminal_tool(
             approval = _check_all_guards(command, env_type)
             if not approval["approved"]:
                 # Check if this is an approval_required (gateway ask mode)
-                if approval.get("status") == "approval_required":
+                if approval.get("status") == "pending_approval":
                     return json.dumps({
                         "output": "",
                         "exit_code": -1,
-                        "error": approval.get("message", "Waiting for user approval"),
-                        "status": "approval_required",
+                        "error": "",
+                        "status": "pending_approval",
+                        "approval_pending": True,
                         "command": approval.get("command", command),
                         "description": approval.get("description", "command flagged"),
                         "pattern_key": approval.get("pattern_key", ""),