Read and control the house through Home Assistant (#256)

A `smarthome` block points Maven at a Home Assistant instance. She reads its
entity states to answer "что включено дома?", and every controllable device
becomes a PROPOSED row in the existing act allowlist — cmd
["smarthome",<entity_id>,<service>], scope smarthome:<domain> — so nothing new
had to be invented for the mutating half. ProposeTool/EnableTool/DisableTool,
tool.Matcher and the confirm turn are untouched; one branch in Executor.Exec
routes such a row to the client instead of exec, and "smarthome" is never run as
a binary. This is the same trick overnight/mcp-tools used for #251, on purpose.

Discovery only ever PROPOSES, and every control row is destructive=true: there
is no read-only way to turn the heating off, so flipping something in his flat
always costs a confirm turn and always had to be enabled by hand on /tools,
behind step-up.

The entity and the service come from the row he enabled, never from the
utterance — Exec drops the spoken tail for a house row. A router that misheard
can pick the wrong lamp; it cannot compose a target of its own. The service is
checked against the domain's table on the way out too, so a hand-edited cmd
column cannot reach an arbitrary Home Assistant service. set_brightness and
set_temperature are deliberately absent: a spoken number the router got wrong is
a wrong act on real hardware, and on/off is the whole of what a voice turn can
defend.

The read side is a query source ("home", before calendar and the recall passes)
so "что нового дома?" is not answered from an old note. Its matcher needs a
house marker plus an ask plus a device word and bails out on weather wording,
because "какая температура на улице?" belongs to the weather source.

Off unless configured: the block is dark without "enabled": true, and
applyDefaults normalises a disabled block to nil so "off" stays in one place.
deploy/mavend.json carries it disabled, with the token as ${HA_TOKEN}.

NOT shipped, and not faked: MQTT / Zigbee2MQTT (plan steps 2 and 5) and the
sensor-to-fact and presence-probe pipelines. There is no broker and no Home
Assistant anywhere on this network — 8123 and 1883 are closed on every host in
192.168.1.0/24 — the module tree is vendored so a paho dependency cannot be
added offline, and Home Assistant already fronts Zigbee2MQTT where it exists.
Writing a sensor pipeline with no sensor to test it against would be a guess.

Vikunja #256

cmd/mavend/actions_query.go

@@ -74,6 +74,13 @@ var querySources = []querySource{
 	// it by inventing news. Its matcher needs a feed noun plus an ask, so
 	// "у меня новая лента в инстаграме" is untouched.
 	{"feeds", (*reactiveHandler).queryFeeds},
+	// Before "calendar" and before the recall sources: "что включено дома?" is
+	// a question about the house, and the notes pass would otherwise answer it
+	// from whatever he once said about the lights. Its matcher needs a house
+	// marker plus an ask plus a device word, and it bails out on weather
+	// wording, so "какая температура на улице?" still reaches the weather
+	// source.
+	{"home", (*reactiveHandler).queryHome},
 	{"calendar", (*reactiveHandler).queryCalendar},
 	{"weather", (*reactiveHandler).queryWeather},
 	{"embed", (*reactiveHandler).queryEmbed},
@@ -275,6 +282,23 @@ func (h *reactiveHandler) queryCalendar(ctx context.Context, t *queryTurn) (stri
 	return f.FormatEntries(entries, date), true
 }
 
+// queryHome answers a question about the house. Read-only by construction: it
+// calls States and nothing else, so there is no confirm turn here — the only
+// way to CHANGE something is an enabled allowlist row through tool.Executor.
+func (h *reactiveHandler) queryHome(ctx context.Context, t *queryTurn) (string, bool) {
+	if !isHomeQuery(t.dec.Utterance) {
+		return "", false
+	}
+	if h.home == nil {
+		// Claim the turn rather than fall through: "дом не подключён" is true,
+		// and letting general knowledge answer would be an invented house.
+		return "дом не подключён — я его не вижу.", true
+	}
+	ctxH, cancel := context.WithTimeout(ctx, 10*time.Second)
+	defer cancel()
+	return h.home.homeSummary(ctxH)
+}
+
 func (h *reactiveHandler) queryWeather(ctx context.Context, t *queryTurn) (string, bool) {
 	if !isWeatherQuery(t.dec.Utterance) {
 		return "", false