fix(app-server): identify MCP approval prompts

Summary:
- Auto-answer only requestUserInput questions with the MCP approval ID marker.
- Keep generic Allow/Deny option prompts blocked for operator input.

Rationale:
- Option labels alone are not a safe approval discriminator; ordinary tool
  prompts can also offer an Allow choice.
- The existing Codex MCP approval question ID distinguishes the narrow prompt
  shape that Symphony may continue automatically.

Tests:
- red/green generic Allow/Deny tool-input regression
- recognized MCP approval prompt regression
- mise exec -- mix test test/symphony_elixir/app_server_test.exs
- HEX_HOME=/private/tmp/symphony-hex mise exec -- make -C elixir all

Co-authored-by: Codex <codex@openai.com>

Author: frantic-openai

elixir/lib/symphony_elixir/codex/app_server.ex

@@ -856,9 +856,13 @@ defmodule SymphonyElixir.Codex.AppServer do
 
   defp tool_request_user_input_approval_answer(%{"id" => question_id, "options" => options})
        when is_binary(question_id) and is_list(options) do
-    case tool_request_user_input_approval_option_label(options) do
-      nil -> :error
-      answer_label -> {:ok, question_id, answer_label}
+    if String.starts_with?(question_id, "mcp_tool_call_approval_") do
+      case tool_request_user_input_approval_option_label(options) do
+        nil -> :error
+        answer_label -> {:ok, question_id, answer_label}
+      end
+    else
+      :error
     end
   end
 

elixir/test/symphony_elixir/app_server_test.exs

@@ -815,7 +815,7 @@ defmodule SymphonyElixir.AppServerTest do
             ;;
           4)
             printf '%s\\n' '{\"id\":3,\"result\":{\"turn\":{\"id\":\"turn-719\"}}}'
-            printf '%s\\n' '{\"id\":112,\"method\":\"item/tool/requestUserInput\",\"params\":{\"itemId\":\"call-719\",\"questions\":[{\"header\":\"Choose an action\",\"id\":\"options-719\",\"isOther\":false,\"isSecret\":false,\"options\":[{\"description\":\"Use the default behavior.\",\"label\":\"Use default\"},{\"description\":\"Skip this step.\",\"label\":\"Skip\"}],\"question\":\"How should I proceed?\"}],\"threadId\":\"thread-719\",\"turnId\":\"turn-719\"}}'
+            printf '%s\\n' '{\"id\":112,\"method\":\"item/tool/requestUserInput\",\"params\":{\"itemId\":\"call-719\",\"questions\":[{\"header\":\"Choose an action\",\"id\":\"options-719\",\"isOther\":false,\"isSecret\":false,\"options\":[{\"description\":\"Proceed with the requested action.\",\"label\":\"Allow\"},{\"description\":\"Do not proceed.\",\"label\":\"Deny\"}],\"question\":\"How should I proceed?\"}],\"threadId\":\"thread-719\",\"turnId\":\"turn-719\"}}'
             ;;
           5)
             printf '%s\\n' '{\"method\":\"turn/completed\"}'
@@ -832,7 +832,8 @@ defmodule SymphonyElixir.AppServerTest do
 
       write_workflow_file!(Workflow.workflow_file_path(),
         workspace_root: workspace_root,
-        codex_command: "#{codex_binary} app-server"
+        codex_command: "#{codex_binary} app-server",
+        codex_approval_policy: "never"
       )
 
       issue = %Issue{