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/models.go

@@ -46,6 +46,8 @@ type AgentSession struct {
 	Summary          string
 	EntityID         *uuid.UUID
 	CompletionNudges int32
+	Blocker          string
+	ClosedAt         *time.Time
 }
 
 type Approval struct {
@@ -110,6 +112,8 @@ type CheckDef struct {
 	Zone       *string
 	Enabled    bool
 	UpdatedAt  time.Time
+	// When this check last executed. NULL = never, due immediately. Compared against interval_s to decide due-ness.
+	LastRunAt *time.Time
 }
 
 type Classification struct {
@@ -177,6 +181,8 @@ type EntityType struct {
 	Status          string
 	CreatedAt       time.Time
 	UpdatedAt       time.Time
+	// Check kinds this type warrants, resolved through parent_type. NULL means undeclared (an ontology gap), [] means explicitly unmonitorable, ["http","resource"] means declared kinds. Populated from seeds/ontology.yaml.
+	MonitoringSpec []byte
 }
 
 type Event struct {
@@ -211,6 +217,14 @@ type Execution struct {
 	CreatedAt        time.Time
 }
 
+type ExecutionLog struct {
+	ExecutionID uuid.UUID
+	Ts          time.Time
+	Seq         int32
+	Stream      string
+	Chunk       string
+}
+
 type Feedback struct {
 	EntityID              uuid.UUID
 	ExecutionID           uuid.UUID