Fix Loki-Metrics initialization race condition

[DavidePrincipi]

This PR enables the Metrics module to access Loki metrics like other applications:

• Allow anonymous access to Prometheus /metrics endpoint
• Publish endpoint configuration in Redis, as specified by Metrics README

This change resolves a config race condition during cluster initialization between Loki and Metrics.

See also NethServer/ns8-metrics#45

Refs NethServer/dev#7780

[Copilot]

Pull request overview

This PR resolves a configuration race condition during cluster initialization between Loki and Metrics modules by enabling the Metrics module to discover and scrape Loki's Prometheus metrics endpoint.

Changes:

• Adds anonymous access to Loki's /metrics endpoint via Traefik routing configuration
• Creates a provisioning script that publishes Loki's metrics endpoint to Redis for Metrics module discovery
• Implements the script in both create-module and update-module.d directories for initial setup and updates

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 6 comments.

File	Description
imageroot/update-module.d/80provision_metrics	Symlink to provision script for module updates
imageroot/scripts/expandconfig-traefik	Adds unauthenticated /metrics route with priority 100
imageroot/actions/create-module/80provision_metrics	Publishes metrics endpoint configuration to Redis

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.