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/commands/project_commands.rs

@@ -160,6 +160,7 @@ pub async fn start_project_container(
                     &project,
                     settings.global_claude_instructions.as_deref(),
                     &settings.global_custom_env_vars,
+                    settings.timezone.as_deref(),
                 )
                 .await
                 .unwrap_or(false);
@@ -175,6 +176,7 @@ pub async fn start_project_container(
                     &settings.global_aws,
                     settings.global_claude_instructions.as_deref(),
                     &settings.global_custom_env_vars,
+                    settings.timezone.as_deref(),
                 ).await?;
                 docker::start_container(&new_id).await?;
                 new_id
@@ -191,6 +193,7 @@ pub async fn start_project_container(
                 &settings.global_aws,
                 settings.global_claude_instructions.as_deref(),
                 &settings.global_custom_env_vars,
+                settings.timezone.as_deref(),
             ).await?;
             docker::start_container(&new_id).await?;
             new_id