orch: require explicit dispatch execution mode

skills/orch/assets/orch-worker-brief

@@ -90,6 +90,7 @@ attempt_no="$(jq -r '.data.attempt.attempt_no // empty' "${dispatch_json}")"
 assigned_to="$(jq -r '.data.attempt.assigned_to // .data.task.default_to // empty' "${dispatch_json}")"
 thread_id="$(jq -r '.data.attempt.thread_id // .data.thread.thread_id // empty' "${dispatch_json}")"
 worktree_path="$(jq -r '.data.attempt.worktree_path // empty' "${dispatch_json}")"
+execution_mode="$(jq -r '.data.message.payload_json.execution_mode // empty' "${dispatch_json}")"
 base_ref="$(jq -r '.data.attempt.base_ref // empty' "${dispatch_json}")"
 task_title="$(jq -r '.data.task.title // empty' "${dispatch_json}")"
 task_summary="$(jq -r '.data.task.summary // empty' "${dispatch_json}")"
@@ -100,9 +101,17 @@ if [ -z "${run_id}" ] || [ -z "${task_id}" ] || [ -z "${assigned_to}" ] || [ -z
   exit 1
 fi
 
-mode="analysis"
-if [ -n "${worktree_path}" ]; then
-  mode="code"
+if [ "${execution_mode}" != "analysis" ] && [ "${execution_mode}" != "code" ]; then
+  printf 'dispatch json is missing a supported execution_mode in message.payload_json\n' >&2
+  exit 1
+fi
+if [ "${execution_mode}" = "code" ] && [ -z "${worktree_path}" ]; then
+  printf 'dispatch json is inconsistent: execution_mode=code requires a worktree_path\n' >&2
+  exit 1
+fi
+if [ "${execution_mode}" = "analysis" ] && [ -n "${worktree_path}" ]; then
+  printf 'dispatch json is inconsistent: execution_mode=analysis must not include a worktree_path\n' >&2
+  exit 1
 fi
 
 cat <<EOF
@@ -114,7 +123,7 @@ You are assigned one existing attempt:
 - attempt_no: ${attempt_no}
 - assigned_to: ${assigned_to}
 - thread_id: ${thread_id}
-- execution_mode: ${mode}
+- execution_mode: ${execution_mode}
 EOF
 
 if [ -n "${task_title}" ]; then