feat: add minimum notification interval for email batching

Add MinNotifyIntervalS config option to batch email notifications over a
time interval. When configured, Gogios only sends an email when:
1. The interval has elapsed since the last notification, AND
2. There's been a state change since the last notification.

HTML status page and text reports continue updating on every run.
The --force flag bypasses the interval for immediate notifications.

Notification state (timestamp + check states snapshot) is persisted to
{StateDir}/notify_state.json for comparison across runs.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

0 files changed, 0 insertions, 0 deletions