mavend: a question about attention reaches Praxis (V-475)

The capability was built, wired and degrading correctly, and no utterance
could reach it. Its aliases sit on the act dispatch, "что требует внимания"
routes to a query, and every query source passed — so the turn fell to the
web search and came back with an article about the concept of attention.
That reads as an answer, which is worse than silence.

queryAttention sits next to "tasks", above the recall sources and well above
the personal boundary: it is operational state about his things, and a notes
pass would otherwise answer from whatever he once wrote about a server. It
calls the same handler the act path calls, so the outage string comes free.

An absent or unconfigured Praxis falls through instead of claiming the turn,
like queryHome and queryNetwork. A configured Praxis that is down claims it
and names the gap. "что нового" is left to the feeds source.

cmd/mavend/actions_query.go

@@ -81,6 +81,11 @@ var querySources = []querySource{
 	// matcher requires a task noun or an explicit "что … сделать", so a
 	// date-bearing question still reaches the calendar.
 	{name: "tasks", answer: (*reactiveHandler).queryTasks},
+	// Next to "tasks" and for the same reason: "что требует внимания?" is a
+	// question about the operational state Praxis holds, and it used to fall
+	// through every source to the web search (Vikunja #475). Its matcher needs
+	// an attention marker, and it falls through when Praxis is not configured.
+	{name: "attention", answer: (*reactiveHandler).queryAttention},
 	// Before the recall sources too: "сколько я потратил?" is a question about
 	// the money facts the poller wrote, and the notes pass would otherwise
 	// answer it from whatever he once said about spending. Its matcher needs a