v0.5.0

Added

• Unified notification system (AI-CLI-25): Notifier class with parallel multi-channel delivery (Discord webhook, ntfy push, OS native). All configured channels fire concurrently; OS notification fires as fallback when all primary channels fail.
• NotificationResult dataclass with per-channel success/failure tracking (channel, status_code, error).
• notification_log SQLite table in quota.db — persistent delivery history with per-row JSON lists of attempted/succeeded/failed channels.
• ai notifications log command — query notification history with --last N, --since DATETIME, --from DATE, --to DATE, --source TEXT, --failed filters. Relative time expressions supported (2h, 30m, 1d, yesterday).
• ai notifications list command — audit configured channels showing name, enabled status, and whether credentials are present (no values exposed).
• ai quota watch is now a command group with start, stop, status, and run subcommands. run is the raw Circus entry point; start/stop/status are the user-facing dispatchers.
• Quota-watch auto-start at session launch (idempotent ai quota watch start in session bash template).
• _notify_threshold() helper routes quota threshold alerts through Notifier with priority and tag mapping (urgent/rotating_light at ≥90%, high/warning at ≥75%).

Changed

• quota_watch() daemon no longer has a PID file guard — Circus owns restart/lifecycle. NATS connection failure is non-fatal; quota watch runs without NATS if unavailable.
• Notification send functions (_send_notification, _send_webhook_notification, _send_ntfy_notification) removed from quota.py and replaced by channel driver functions (_send_discord, _send_ntfy, _send_os_notification) in notifications.py.