docs: move inspect and advisors into observability - #49503

Stack

Draft stack extracted from docs/monitoring. Merge bottom-up. Troubleshooting / debugging-guide rewrite is out of scope.

1. docs: move inspect and advisors into observability #49503 move inspect and advisors ← this PR
2. docs: split Studio logs from ClickHouse log queries #49501 split Studio logs from ClickHouse queries
3. docs: treat reports as signal dashboards, not fix lists #49500 treat reports as signal dashboards
4. docs: add Observe the data hub for logs, metrics, and advisors #49502 add Observe the data hub
5. docs: add reusable monitoring agent setup components #49506 add agent setup components
6. docs: add hire-an-agent templates for observability routines #49504 add hire-an-agent templates
7. docs: restructure observability navigation and overview #49505 restructure observability nav and overview

I have read the CONTRIBUTING.md file.

YES

What kind of change does this PR introduce?

Docs update. First layer in the observability stack.

What is the current behavior?

Inspect and advisors live under Database (/guides/database/inspect, /guides/database/database-advisors). Observability readers have to leave the monitoring section to find them.

What is the new behavior?

• Moves inspect into /guides/monitoring-and-debugging/inspect
• Adds /guides/monitoring-and-debugging/advisors (replaces the Database Advisors page)
• Adds redirects and updates Studio/docs links so old URLs keep working
• Adds both pages to the existing Monitoring nav so they are discoverable before the later IA PR

Additional context

Inspect and advisors pages render as standard MDX. Redirects cover /docs/guides/database/inspect, /docs/guides/database/database-advisors, and /docs/guides/database/database-linter. Debugging-guide content is unchanged except the inspect URL.

Self-review

• No leftover /guides/database/inspect or /guides/database/database-advisors links in docs guides or Studio linter/AI surfaces (historical blog posts left as-is)
• Smoke test path updated to /docs/guides/monitoring-and-debugging/advisors