feat(app-core): wire compaction hook + register compaction_hooks module

Beads: jcode-afp (restore_todos_after_compaction — done in jcode-wje)
       jcode-h08 (wire compaction hook into compaction.rs)

* Added pub(crate) mod compaction_hooks; to server.rs
* Wired restore_todos_after_compaction into Agent::poll_compaction_completion_event
  after note_compaction_applied(). Handles error via crate::logging::warn
  (never aborts compaction).
* message_to_json_value helper converts session messages for the transcript scan.
* Fixed compaction_hooks.rs imports to use correct type names
  (TodoEvent not TodoUpdated, String status not TodoStatus).

Author: quangdang46

crates/jcode-app-core/src/agent/compaction.rs

@@ -26,6 +26,29 @@ impl Agent {
             self.note_compaction_applied();
             self.persist_session_best_effort("compaction completion");
 
+            // Restore todos from the post-compaction message log so the
+            // model retains task context after compaction. Source pattern:
+            // claude-code v1 sessionRestore.ts:extractTodosFromTranscript.
+            // Fail-safe: tracing::warn on error, never abort compaction.
+            {
+                use crate::server::compaction_hooks::restore_todos_after_compaction;
+                let messages_json: Vec<serde_json::Value> = self
+                    .session
+                    .messages_for_provider()
+                    .iter()
+                    .map(message_to_json_value)
+                    .collect();
+                if let Err(e) = restore_todos_after_compaction(
+                    &self.session.id,
+                    &messages_json,
+                ) {
+                    crate::logging::warn(&format!(
+                        "failed to restore todos after compaction for session={}: {e}",
+                        self.session.id,
+                    ));
+                }
+            }
+
             // PostCompact hook (fire-and-forget)
             let registry = self.hook_registry.clone();
             let config = self.dispatch_config.clone();
@@ -532,3 +555,11 @@ impl Agent {
         };
     }
 }
+
+/// Convert a stored Message to a generic JSON value for the compaction-hooks
+/// transcript scan. Shape: `{role, content}` where content is the array of
+/// content blocks (text + tool_use). Best-effort serialization; any failure
+/// yields Null and the scan simply skips that message.
+fn message_to_json_value(message: &crate::message::Message) -> serde_json::Value {
+    serde_json::to_value(message).unwrap_or(serde_json::Value::Null)
+}

crates/jcode-app-core/src/server.rs

@@ -1,6 +1,7 @@
 mod await_members_state;
 mod background_tasks;
 mod client_actions;
+pub(crate) mod compaction_hooks;
 mod client_api;
 mod client_comm;
 mod client_comm_channels;

crates/jcode-app-core/src/server/compaction_hooks.rs

@@ -7,10 +7,11 @@
 //! block cuối cùng của tool "todo", restore state. Zero in-memory state,
 //! fail-safe.
 
-use crate::bus::{Bus, BusEvent, TodoUpdated};
+use crate::bus::{Bus, BusEvent, TodoEvent};
 use anyhow::Result;
+
 use chrono::Utc;
-use jcode_task_types::{TodoItem, TodoStatus};
+use jcode_task_types::TodoItem;
 use serde_json::Value;
 
 /// Extract most recent todo list from message log.
@@ -66,15 +67,15 @@ fn parse_one(item: Value) -> Option<TodoItem> {
     let content = item.get("content")?.as_str()?.to_string();
     let status_str = item.get("status")?.as_str()?;
     let status = match status_str {
-        "pending" => TodoStatus::Pending,
-        "in_progress" => TodoStatus::InProgress,
-        "completed" => TodoStatus::Completed,
-        "blocked" => TodoStatus::Blocked,
+        "pending" => "pending",
+        "in_progress" => "in_progress",
+        "completed" => "completed",
+        "blocked" => "blocked",
         _ => return None,
     };
     Some(TodoItem {
         content,
-        status,
+        status: status.to_string(),
         active_form: item
             .get("active_form")
             .and_then(|v| v.as_str())
@@ -94,10 +95,9 @@ pub fn restore_todos_after_compaction(
         return Ok(Vec::new());
     }
     crate::todo::save_todos(session_id, &todos)?;
-    Bus::global().publish(BusEvent::TodoUpdated(TodoUpdated {
+    Bus::global().publish(BusEvent::TodoUpdated(TodoEvent {
         session_id: session_id.to_string(),
         todos: todos.clone(),
-        at: Utc::now(),
     }));
     Ok(todos)
 }
@@ -132,7 +132,7 @@ mod tests {
         let todos = extract_todos_from_transcript(&messages);
         assert_eq!(todos.len(), 2);
         assert_eq!(todos[0].content, "task A");
-        assert_eq!(todos[1].status, TodoStatus::InProgress);
+        assert_eq!(todos[1].status, "in_progress");
     }
 
     #[test]