feat: Add new API endpoints (health, summary, uptime, incidents)

New endpoints:
- GET /api/health - Simple health check, always public (for load balancers)
- GET /api/summary - Lightweight status overview (counts + overall status)
- GET /api/uptime/{name}?period=1h|24h|7d|30d|90d - Historical uptime stats
- GET /api/incidents?filter=all|active|resolved|scheduled - List incidents

All new endpoints (except /api/health) follow api.access rules.

1 files changed, 37 insertions, 0 deletions

diff --git a/internal/storage/sqlite.go b/internal/storage/sqlite.go
index e441fe7..3d89cb1 100644
--- a/internal/storage/sqlite.go
+++ b/internal/storage/sqlite.go
@@ -496,6 +496,43 @@ func (s *Storage) GetUptimeHistory(ctx context.Context, monitorName string, days
 	return result, nil
 }
 
+// UptimeStats contains uptime statistics for a period
+type UptimeStats struct {
+	UptimePercent float64
+	TotalChecks   int64
+	SuccessChecks int64
+	FailedChecks  int64
+}
+
+// GetUptimeStats returns uptime statistics for a monitor over a given duration
+func (s *Storage) GetUptimeStats(ctx context.Context, monitorName string, duration time.Duration) (*UptimeStats, error) {
+	cutoff := time.Now().Add(-duration)
+
+	var totalChecks, successChecks int64
+	err := s.db.QueryRowContext(ctx, `
+		SELECT 
+			COUNT(*) as total,
+			SUM(CASE WHEN status = 'up' THEN 1 ELSE 0 END) as success
+		FROM check_results
+		WHERE monitor_name = ? AND timestamp >= ?
+	`, monitorName, cutoff).Scan(&totalChecks, &successChecks)
+	if err != nil {
+		return nil, fmt.Errorf("failed to query uptime stats: %w", err)
+	}
+
+	stats := &UptimeStats{
+		TotalChecks:   totalChecks,
+		SuccessChecks: successChecks,
+		FailedChecks:  totalChecks - successChecks,
+	}
+
+	if totalChecks > 0 {
+		stats.UptimePercent = float64(successChecks) / float64(totalChecks) * 100
+	}
+
+	return stats, nil
+}
+
 // PingResult represents a single ping for the history display
 type PingResult struct {
 	Status       string // up, down, degraded