Keep hook context out of rollback trimming

codex-rs/core/src/context_manager/history_tests.rs

@@ -902,7 +902,6 @@ fn drop_last_n_user_turns_trims_context_updates_above_rolled_back_turn() {
         user_input_text_msg("turn 1 user"),
         assistant_msg("turn 1 assistant"),
         developer_msg("Generated images are saved to /tmp as /tmp/image-1.png by default."),
-        developer_msg("<hook_context>ROLLED_BACK_HOOK_CONTEXT</hook_context>"),
         developer_msg("<collaboration_mode>ROLLED_BACK_DEV_INSTRUCTIONS</collaboration_mode>"),
         user_input_text_msg(
             "<environment_context><cwd>PRETURN_CONTEXT_DIFF_CWD</cwd></environment_context>",

codex-rs/core/src/event_mapping.rs

@@ -30,7 +30,6 @@ const CONTEXTUAL_DEVELOPER_PREFIXES: &[&str] = &[
     COLLABORATION_MODE_OPEN_TAG,
     REALTIME_CONVERSATION_OPEN_TAG,
     "<personality_spec>",
-    "<hook_context>",
 ];
 
 pub(crate) fn is_contextual_user_message_content(message: &[ContentItem]) -> bool {