fix(scheduler): honour check_defs.interval_s, and renumber migrations off main

ListEnabledCheckDefs selected interval_s but never filtered on it, so every
enabled check ran on every 30s pass and the declared per-check intervals were
decorative. Invisible at 17 enabled checks; at ~180 it would have meant ~126
SSH connections every 30s (~363k/day) and `apt update` on every machine every
30 seconds — 14,400 mirror hits a day to answer a question that changes daily.

- check_defs.last_run_at (migration 026) + a due-ness predicate in the query.
  A column rather than scheduler memory because this control plane restarts on
  every deploy, and an in-memory map would re-fire every check on each restart.
- runCheck stamps last_run_at before processing the result, so a permanently
  failing check backs off to its interval instead of re-running every pass.
- updates and backup-freshness drop to daily. Both answer questions whose
  answers change about once a day; 60s was just the shared ssh-script default.
- last_run_at is seeded to a random offset within the interval so checks
  created by the same seed do not stay in lockstep — otherwise ~165 probes
  land in the same instant each minute instead of spread across it.
  Deliberately not in the upsert's DO UPDATE: a re-seed must not re-herd them.

Steady state becomes ~180k SSH/day (down from ~363k) and 5 apt runs/day
(down from 14,400), with each 60s check landing at its own point in the minute.

Also renumbers 022→023, 023→024, 024→025: origin/main added its own
022_knowledge_revisions, and prod has already applied version 22. Left
colliding, prod would have skipped the monitoring_spec migration entirely and
then failed the seed on a missing column.

Co-Authored-By: Claude <noreply@anthropic.com>

internal/db/sqlcgen/ontology.sql.go

@@ -30,7 +30,7 @@ func (q *Queries) GetLifecycleForType(ctx context.Context, name string) (Lifecyc
 }
 
 const listEntityTypes = `-- name: ListEntityTypes :many
-SELECT name, parent_type, is_abstract, domain, layer, description, lifecycle_id, attribute_schema, schema_version, status, created_at, updated_at FROM entity_types ORDER BY name
+SELECT name, parent_type, is_abstract, domain, layer, description, lifecycle_id, attribute_schema, schema_version, status, created_at, updated_at, monitoring_spec FROM entity_types ORDER BY name
 `
 
 func (q *Queries) ListEntityTypes(ctx context.Context) ([]EntityType, error) {
@@ -55,6 +55,7 @@ func (q *Queries) ListEntityTypes(ctx context.Context) ([]EntityType, error) {
 			&i.Status,
 			&i.CreatedAt,
 			&i.UpdatedAt,
+			&i.MonitoringSpec,
 		); err != nil {
 			return nil, err
 		}