feat(ui): M4 — agent activity, knowledge search, audit, correlation grouping

Add three new pages completing the control-room web UI:
- Agent activity: polls /agent-activity every 5s, filterable by type/agent
- Knowledge search: FTS over /knowledge/search with snippet + entity links
- Audit trail: browseable audit log with actor/action/entity filters

Enhanced live events page with correlation-id clustering (Groups toggle).
Added fetchAgentActivity/searchKnowledge/fetchAudit to the API client.
11 nav items now cover all planned control-room views.

internal/httpapi/impl.go

@@ -322,9 +322,44 @@ func (s *Server) GetGraph(ctx context.Context, req gen.GetGraphRequestObject) (g
 	if truncated {
 		resp.Truncated = &truncated
 	}
+
+	if req.Params.Include != nil {
+		for _, inc := range *req.Params.Include {
+			if inc == gen.Status {
+				health, herr := s.entityHealthByID(ctx, ids)
+				if herr != nil {
+					return nil, herr
+				}
+				resp.Health = &health
+				break
+			}
+		}
+	}
+
 	return resp, nil
 }
 
+// entityHealthByID returns entity_status.health keyed by entity id, for the
+// given id set (used by GetGraph's include=status).
+func (s *Server) entityHealthByID(ctx context.Context, ids []uuid.UUID) (map[string]gen.GraphViewHealth, error) {
+	health := make(map[string]gen.GraphViewHealth, len(ids))
+	rows, err := s.pool.Query(ctx,
+		`SELECT entity_id, health FROM entity_status WHERE entity_id = ANY($1)`, ids)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	for rows.Next() {
+		var id uuid.UUID
+		var h string
+		if err := rows.Scan(&id, &h); err != nil {
+			return nil, err
+		}
+		health[id.String()] = gen.GraphViewHealth(h)
+	}
+	return health, rows.Err()
+}
+
 func (s *Server) queryEntities(ctx context.Context, query string, args ...any) ([]gen.Entity, error) {
 	rows, err := s.pool.Query(ctx, query, args...)
 	if err != nil {