[jayunit100]

Summary

• The 1.x Substrate telemetry page linked docs/observability.md on Agent Substrate. That path returns 404.
• Point "Actor observability" at docs/guides/observability.md, which returns 200 and is the current guide.
• Fixes Docs: Substrate telemetry page links to a removed observability path #684. The link checker report in Link Checker Report - kagent OSS #663 lists this 404; the broken API-reference anchors there are unchanged.

Test plan

• curl the old URL returns 404 and the new URL returns 200
• Hugo 0.160.1 extended build of docs-site (hugo --config hugo.yaml --gc --minify) succeeds
• Built HTML and markdown for kagent/1.x/observability/substrate-telemetry contain docs/guides/observability.md and not docs/observability.md

Made with Cursor

[peterj]

@jayunit100 thanks for the PR -- can you sign the DCO please?