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/lib/tauri-commands.ts

@@ -35,6 +35,8 @@ export const detectAwsConfig = () =>
   invoke<string | null>("detect_aws_config");
 export const listAwsProfiles = () =>
   invoke<string[]>("list_aws_profiles");
+export const detectHostTimezone = () =>
+  invoke<string>("detect_host_timezone");
 
 // Terminal
 export const openTerminalSession = (projectId: string, sessionId: string) =>