chore: rework tools execution workflow (#5278)

Re-work the tool execution flow. Read `orchestrator.rs` to understand
the structure

codex-rs/core/src/state/service.rs

@@ -2,9 +2,8 @@ use std::sync::Arc;
 
 use crate::AuthManager;
 use crate::RolloutRecorder;
-use crate::exec_command::ExecSessionManager;
-use crate::executor::Executor;
 use crate::mcp_connection_manager::McpConnectionManager;
+use crate::tools::sandboxing::ApprovalStore;
 use crate::unified_exec::UnifiedExecSessionManager;
 use crate::user_notification::UserNotifier;
 use codex_otel::otel_event_manager::OtelEventManager;
@@ -12,13 +11,12 @@ use tokio::sync::Mutex;
 
 pub(crate) struct SessionServices {
     pub(crate) mcp_connection_manager: McpConnectionManager,
-    pub(crate) session_manager: ExecSessionManager,
     pub(crate) unified_exec_manager: UnifiedExecSessionManager,
     pub(crate) notifier: UserNotifier,
     pub(crate) rollout: Mutex<Option<RolloutRecorder>>,
     pub(crate) user_shell: crate::shell::Shell,
     pub(crate) show_raw_agent_reasoning: bool,
-    pub(crate) executor: Executor,
     pub(crate) auth_manager: Arc<AuthManager>,
     pub(crate) otel_event_manager: OtelEventManager,
+    pub(crate) tool_approvals: Mutex<ApprovalStore>,
 }