Fix goal-first live threads missing from thread/list (#28808)

Fixes #28263.

## Why

When a thread starts with `/goal`, the goal extension can update SQLite
goal state before the thread has any user-turn rollout items.
`thread/list` and `thread/search` rely on persisted listing metadata, so
a goal-first live thread could be absent from app-server listings after
restart even though the goal itself existed.

This regressed when goal handling moved out of core: the core path wrote
the goal update through the live thread rollout path, while the
extension-backed app-server path only updated goal state and emitted the
live notification.

## What

- Add `GoalSetOutcome::thread_goal_updated_item()` so the goal extension
owns the canonical `ThreadGoalUpdated` rollout item shape.
- Expose a narrow `CodexThread::append_rollout_items()` helper that
appends through the live thread and keeps derived SQLite metadata in
sync.
- When app-server sets a goal on an active live thread, persist the goal
update through that live-thread path.
- Add an app-server regression test that starts a live thread with
`thread/goal/set` and verifies it appears in state-DB-only
`thread/list`.

## Verification

- `env -u CODEX_SQLITE_HOME just test -p codex-app-server
goal_first_live_thread_appears_in_state_db_thread_list`

codex-rs/core/src/codex_thread.rs

@@ -24,6 +24,7 @@ use codex_protocol::protocol::AskForApproval;
 use codex_protocol::protocol::Event;
 use codex_protocol::protocol::MultiAgentVersion;
 use codex_protocol::protocol::Op;
+use codex_protocol::protocol::RolloutItem;
 use codex_protocol::protocol::SandboxPolicy;
 use codex_protocol::protocol::SessionConfiguredEvent;
 use codex_protocol::protocol::SessionSource;
@@ -535,6 +536,18 @@ impl CodexThread {
         live_thread.update_metadata(patch, include_archived).await
     }
 
+    /// Appends rollout items through the live thread so derived metadata stays in sync.
+    pub async fn append_rollout_items(&self, items: &[RolloutItem]) -> ThreadStoreResult<()> {
+        let live_thread = self
+            .codex
+            .session
+            .live_thread_for_persistence("append rollout items")
+            .map_err(|err| ThreadStoreError::Internal {
+                message: err.to_string(),
+            })?;
+        live_thread.append_items(items).await
+    }
+
     pub fn state_db(&self) -> Option<StateDbHandle> {
         self.codex.state_db()
     }