[User Story] Add automated version detection and build triggers

[noahwhite]

Description

Create automation to detect new Grafana Alloy releases and automatically trigger sysext builds, making the system self-updating.

Acceptance Criteria

• Create scheduled workflow to check for new Alloy releases
  • Use GitHub API to check grafana/alloy releases
  • Run on schedule (e.g., daily at midnight UTC)
• Compare against last built version
  • Store last built version in repo (version.txt or similar)
  • Detect when new version is available
• Automatically create release and trigger build for new versions
  • Create new release in alloy-sysext-build repo
  • Trigger existing build workflow
• Send notification when new version is built
  • GitHub Issues (create issue for tracking)
  • Optional: Slack/Discord webhook
  • Include changelog and download links
• Optional: PR automation to update ghost.bu
  • Automatically create PR in ghost repo
  • Update image URL and hash
  • Link to release notes

Technical Implementation

• Use GitHub Actions scheduled workflow (on: schedule)
• Use GitHub API to query grafana/alloy releases
• Use GitHub CLI (gh) for creating releases and PRs
• Consider rate limiting and error handling

Priority

Low - Future enhancement after core migration is complete

Dependencies

• GHO-32 through GHO-37: All core migration tasks must be complete
• Core build pipeline must be stable and reliable

[linear]

GHO-38