feat(web): make the entity window a triage surface, not a data dump

The window rendered the same 13 collapsible sections for every entity, sorted
only by "does it have content". Audit trail carried the same visual weight as
Health, and the window answered "what data do we hold about X?" rather than
"what do I need to know, and what should I do?".

Measured against prod: host:hubris has 223 relations, 1,601 events, 2.7M metric
samples and 148 executions; an ingress route has three facts. Both got 13
identical headers. Expanding a host put ~540 interactive elements on screen.

- **A verdict header that never collapses.** Not just "down" but *why*:
  "ping failing · 5 of 6 checks passing". That line did not previously exist
  and could not have — checks rendered as configuration, never as results.
- **Sections composed per type.** A document has no checks, metrics or blast
  radius; a signal or execution is a record, not a thing. Infrastructure gets
  Status/Impact/Activity/Metrics/Reference, knowledge types lead with Content,
  records get a minimal view. Unknown types fall back to infrastructure so a
  new entity type is never a blank window.
- **Status replaces Monitoring**, showing each check's own verdict and when it
  last ran — the section that answers the header's "why".
- **Impact** finally calls /entities/{id}/blast-radius. The endpoint has existed
  since the first API and had no frontend caller anywhere, despite
  .agents/OIKOS.md naming blast radius as the reason the ontology exists. Its
  outgoing-edges-only limitation is stated in the UI rather than hidden.
- **Activity merges four lists** (executions, signals, events, agent activity)
  that were telling one story in four places.
- **Relations cap at 8 with a drill-in** — 540 interactive elements down to 126.
- **Ask Nomos** opens a task pre-scoped to what you are looking at, seeded with
  the verdict just computed, via an optional draft threaded through
  openNewTaskWindow -> NewTaskChat -> ChatThread.

Requires exposing check_defs.last_health/last_run_at through the API (the
columns landed with the health-aggregation work but were never surfaced).
Adding a fourth enum containing "unknown" made oapi-codegen disambiguate all
enum constants by type prefix, so metrics.go moves to gen.TrendDirection*.

Verdict derivation and type->section composition live in $lib/entityView.ts as
pure functions with 15 unit tests, including the host:strong case that
motivated this.

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

internal/httpapi/checks.go

@@ -22,7 +22,7 @@ func (s *Server) ListChecks(ctx context.Context, req gen.ListChecksRequestObject
 		SELECT cd.entity_id, e.slug, cd.kind,
 		       COALESCE(te.slug, '') AS target_slug, cd.target_type,
 		       cd.config, cd.interval_s, cd.timeout_s, cd.zone, cd.enabled,
-		       e.version
+		       e.version, cd.last_health, cd.last_run_at
 		FROM check_defs cd
 		JOIN entities e ON e.id = cd.entity_id
 		LEFT JOIN entities te ON te.id = cd.target_id
@@ -43,10 +43,19 @@ func (s *Server) ListChecks(ctx context.Context, req gen.ListChecksRequestObject
 		var c gen.Check
 		var targetSlug string
 		var configBytes []byte
+		// last_health is what turns a check list from configuration into an
+		// explanation: an entity's health is the worst of these, so this is
+		// the field that says which probe is responsible.
+		var lastHealth *string
 		if err := rows.Scan(&c.Id, &c.Slug, &c.Kind, &targetSlug, &c.TargetType,
-			&configBytes, &c.IntervalS, &c.TimeoutS, &c.Zone, &c.Enabled, &c.Version); err != nil {
+			&configBytes, &c.IntervalS, &c.TimeoutS, &c.Zone, &c.Enabled, &c.Version,
+			&lastHealth, &c.LastRunAt); err != nil {
 			return nil, err
 		}
+		if lastHealth != nil {
+			h := gen.CheckLastHealth(*lastHealth)
+			c.LastHealth = &h
+		}
 		if targetSlug != "" {
 			c.Target = &targetSlug
 		}
@@ -285,6 +294,15 @@ func checkDefToGen(cd sqlcgen.CheckDef) gen.Check {
 	if len(cd.Config) > 0 && json.Unmarshal(cd.Config, &config) == nil && len(config) > 0 {
 		c.Config = &config
 	}
+	// Carried through so toggling a check does not blank its verdict in the
+	// UI — the entity window renders last_health to explain which probe is
+	// responsible for an entity's health, and a patch response missing it
+	// would erase that until the next poll.
+	c.LastRunAt = cd.LastRunAt
+	if cd.LastHealth != nil {
+		h := gen.CheckLastHealth(*cd.LastHealth)
+		c.LastHealth = &h
+	}
 	return c
 }