mavend: an unconfigured capability names the gap (V-479)

Netscan and the crawler both declined their own turn when the wiring was
nil, and the question fell through to the search leg. "какие устройства в
сети?" came back as a paragraph about routers in general, and a question
about his own LAN went to an upstream engine — the personal boundary
exists to stop exactly that. A URL he named came back answered as though
he had not named it.

Both now claim the turn once their own recogniser has matched, and say
which capability is missing: net_off and page_off in the query family.

TestQueryWebPassesWhenNotConfigured encoded the old decision, that
announcing a configuration status is only for a capability that exists and
failed. It is rewritten, not deleted: the gap is the answer now.

cmd/mavend/actions_query.go

@@ -367,9 +367,12 @@ func (h *reactiveHandler) queryNetwork(ctx context.Context, t *queryTurn) (strin
 		return "", false
 	}
 	if h.netscan == nil {
-		// Fall through, same as queryHome: an unconfigured scanner must not
-		// swallow "сколько устройств в сети?" before recall has looked.
-		return "", false
+		// The recogniser already matched, so this is a question about HIS LAN
+		// and there is no scanner to answer it. Falling through sent it to the
+		// search leg, which answered with a paragraph about routers in general
+		// and put his network question on an upstream engine (Vikunja #479).
+		// A missing capability names itself.
+		return phraser.Q(phraser.QueryNetOff, nil), true
 	}
 	return h.netscan.scanSummary(ctx)
 }
@@ -524,12 +527,11 @@ func (h *reactiveHandler) queryWeb(ctx context.Context, t *queryTurn) (string, b
 		return "", false
 	}
 	if h.crawler == nil {
-		// Fall through. Reading pages is off unless configured, and on a daemon
-		// where it was never turned on the older behaviour is right: the model
-		// answers the question as if the URL had not been said. Announcing a
-		// configuration status is for a capability that exists and failed, not
-		// for one he never asked for.
-		return "", false
+		// He named a URL, so the question is about that page and nothing else
+		// can answer it. The older comment here argued for falling through and
+		// letting the model answer as if the URL had not been said; that is a
+		// guess dressed as an answer (Vikunja #479).
+		return phraser.Q(phraser.QueryPageOff, nil), true
 	}
 	ctxFetch, cancel := context.WithTimeout(ctx, 30*time.Second)
 	defer cancel()