feat(nodes): remote sleep/wake — idle detection + wake-page ingress

Agents report per-container net IO at heartbeat; the sleeper measures
idleness from those counters for remote services, removes replicas via
the agent queue, and repoints the domain route at the backend's new
/internal/wake-page endpoint (replacePath + priority-100 route in the
file provider). First hit serves a reloading page and retriggers the
wake reconcile, which recreates replicas and restores real upstreams.

Manual POST /services/:id/sleep also routes remote; local sleep/wake
flow is unchanged.

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

docs/guides/CLI.md

@@ -161,12 +161,15 @@ containr nodes update <id> --tags gpu,eu-west
 containr services update <id> --placement-tags gpu     # only gpu nodes are eligible
 ```
 
-Remote nodes run registry-pulled images only — git builds and sleep
-detection stay local. Domains work remotely: the agent publishes the
-service port and the backend writes a Traefik file-provider route to the
-node's mesh IP (TRAEFIK_DYNAMIC_DIR — wired by the infra compose).
-Start, stop, restart, redeploy, and delete all fan out to the pinned
-node's agent. `services get` shows the resolved `node_name`.
+Remote nodes run registry-pulled images only — git builds stay local.
+Domains work remotely: the agent publishes the service port and the
+backend writes a Traefik file-provider route to the node's mesh IP
+(TRAEFIK_DYNAMIC_DIR — wired by the infra compose). Sleep mode works
+too: heartbeats carry per-container net counters, idle remote services
+lose their replicas via the agent, and the route repoints at the
+backend's wake page — the next hit reconciles the service back. Start,
+stop, restart, redeploy, and delete all fan out to the pinned node's
+agent. `services get` shows the resolved `node_name`.
 
 Take a node out of rotation or empty it entirely (admin):