feat: add COLO field to access log tracking

Add Cloudflare COLO data to the access log tracking system to capture datacenter location information. This enables better monitoring of request distribution across Cloudflare's global infrastructure.

The COLO field is mapped to blob16 in the blobs map and populated from the Cloudflare request headers.

server/utils/access-log.ts

@@ -34,6 +34,7 @@ export const blobsMap = {
   blob13: 'browserType',
   blob14: 'device',
   blob15: 'deviceType',
+  blob16: 'COLO',
 } as const
 
 export const doublesMap = {
@@ -140,6 +141,7 @@ export function useAccessLog(event: H3Event) {
     browserType: uaInfo?.browser?.type,
     device: uaInfo?.device?.model,
     deviceType: uaInfo?.device?.type,
+    COLO: cf?.colo,
 
     // For RealTime Globe
     latitude: Number(cf?.latitude || getHeader(event, 'cf-iplatitude') || 0),