Draft: feat(schema): serve queries from active ontology archives

What does this MR do and why?

Queries use the active schema's ontology archive, keeping in-flight requests consistent through promotion and rollback. Unusable archives fail closed and recover without restart.

Related Issues

Relates to #184 (closed). Final implementation slice of !2433 (closed), following merged !2439 (merged).

Testing

895 unit tests and four archive-serving contracts pass, alongside Clippy, formatting, docs, metrics, and dashboards. External analytics tests excluded. One broader query-suite failure also reproduces on main.

Performance Analysis

• This merge request does not introduce any performance regression. If a performance regression is expected, explain why.

Agent context

The rebase includes the compiler API adjustment and dashboard synchronization. The existing failure is aggregation_user_reachable_via_path_compiles; isolated reruns pass. Docker checks passed on retry. Not benchmarked; rollout constraints remain.