[codex] Add local thread store listing (#17824)

Builds on top of #17659 

Move the filesystem + sqlite thread listing-related operations inside of
a local ThreadStore implementation and call ThreadStore from the places
that used to perform these filesystem/sqlite operations.

This is the first of a series of PRs that will implement the rest of the
local ThreadStore.

Testing:
- added unit tests for the thread store implementation
- adjusted some unit tests in the realtime + personality packages whose
callsites changed. Specifically I'm trying to hide ThreadMetadata inside
of the local implementation and make ThreadMetadata a sqlite
implementation detail concern rather than a public interface, preferring
the more generate StoredThread interface instead
- added a corner case test for the personality migration package that
wasn't covered by the existing test suite
- adjust the behavior of searched thread listing to run the existing
local rollout repair/backfill pass _before_ querying SQLite results, so
callers using ThreadStore::list_threads do not miss matches after a
partial metadata warm-up

codex-rs/core/src/codex.rs

@@ -136,9 +136,11 @@ use codex_protocol::request_permissions::RequestPermissionsResponse;
 use codex_protocol::request_user_input::RequestUserInputArgs;
 use codex_protocol::request_user_input::RequestUserInputResponse;
 use codex_rmcp_client::ElicitationResponse;
+use codex_rollout::RolloutConfig;
 use codex_rollout::state_db;
 use codex_shell_command::parse_command::parse_command;
 use codex_terminal_detection::user_agent;
+use codex_thread_store::LocalThreadStore;
 use codex_tools::filter_tool_suggest_discoverable_tools_for_client;
 use codex_utils_output_truncation::TruncationPolicy;
 use codex_utils_stream_parser::AssistantTextChunk;
@@ -2127,6 +2129,7 @@ impl Session {
             network_proxy,
             network_approval: Arc::clone(&network_approval),
             state_db: state_db_ctx.clone(),
+            thread_store: LocalThreadStore::new(RolloutConfig::from_view(config.as_ref())),
             model_client: ModelClient::new(
                 Some(Arc::clone(&auth_manager)),
                 conversation_id,