Add container-native scheduled task system with timezone support

Introduces a cron-based scheduler that lets Claude set up recurring and
one-time tasks inside containers. Tasks run as separate Claude Code agents
and persist across container recreation via the named volume.

New files:
- container/triple-c-scheduler: CLI for add/remove/enable/disable/list/logs/run/notifications
- container/triple-c-task-runner: cron wrapper with flock, logging, notifications, auto-cleanup

Key changes:
- Dockerfile: add cron package and COPY both scripts
- entrypoint.sh: timezone setup, cron daemon, crontab restore, env saving
- container.rs: init=true for zombie reaping, TZ env, scheduler instructions, timezone recreation check
- image.rs: embed scheduler scripts in build context
- app_settings.rs + types.ts: timezone field
- settings_commands.rs: detect_host_timezone via iana-time-zone crate
- SettingsPanel.tsx: timezone input with auto-detection

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/src-tauri/src/docker/image.rs

@@ -9,6 +9,8 @@ use crate::models::container_config;
 
 const DOCKERFILE: &str = include_str!("../../../../container/Dockerfile");
 const ENTRYPOINT: &str = include_str!("../../../../container/entrypoint.sh");
+const SCHEDULER: &str = include_str!("../../../../container/triple-c-scheduler");
+const TASK_RUNNER: &str = include_str!("../../../../container/triple-c-task-runner");
 
 pub async fn image_exists(image_name: &str) -> Result<bool, String> {
     let docker = get_docker()?;
@@ -135,6 +137,20 @@ fn create_build_context() -> Result<Vec<u8>, std::io::Error> {
         header.set_cksum();
         archive.append_data(&mut header, "entrypoint.sh", entrypoint_bytes)?;
 
+        let scheduler_bytes = SCHEDULER.as_bytes();
+        let mut header = tar::Header::new_gnu();
+        header.set_size(scheduler_bytes.len() as u64);
+        header.set_mode(0o755);
+        header.set_cksum();
+        archive.append_data(&mut header, "triple-c-scheduler", scheduler_bytes)?;
+
+        let task_runner_bytes = TASK_RUNNER.as_bytes();
+        let mut header = tar::Header::new_gnu();
+        header.set_size(task_runner_bytes.len() as u64);
+        header.set_mode(0o755);
+        header.set_cksum();
+        archive.append_data(&mut header, "triple-c-task-runner", task_runner_bytes)?;
+
         archive.finish()?;
     }