v0.4.0

Added

• SYNCRET_INSTANCE_NAME — optional human-readable label for the deployment, shown in notification headers (e.g., *Syncret — Production*). Must be a single line of at most 64 characters.
• SYNCRET_TIMEZONE — optional IANA timezone for notification timestamps (e.g., America/New_York). Defaults to UTC. Invalid zones fail at startup. Timezone data is embedded in the binary via time/tzdata for Lambda environments.
• Enriched GChat notifications — messages now include AWS account ID, region, source and target secret names (extracted from ARNs), ECS cluster and services, Lambda request ID, and a localized timestamp. Each pipeline stage (target secret update, ECS force-deployment) is reported individually with its outcome (succeeded, failed, skipped, or not attempted). Errors shown in notifications are sanitized; raw details remain in CloudWatch Logs.