maven: calendar event querying (task 3)

Store: CalendarEvents(ctx, from, to) — filters caldav facts by key date prefix.
IPC: full wiring through interface, server dispatch, and client.
Router: ParseCalendarDate (сегодня/завтра), CalendarEventFormatter (RU reply).
Voice: calendar detection before notes RAG in IntentQuery handler.
Tests: store integration test, date parser tests, formatter tests.

Co-Authored-By: opencode <opencode@anthropic.com>

cmd/mavend/voice.go

@@ -411,6 +411,21 @@ func (h *reactiveHandler) applyAction(ctx context.Context, dec router.Decision)
 		return "" // replier phrases the "saved" reply
 
 	case router.IntentQuery:
+		// Calendar questions: "что у меня сегодня?", "планы на завтра?"
+		if date, ok := router.ParseCalendarDate(dec.Utterance, time.Now()); ok {
+			events, err := h.api.CalendarEvents(ctx, date, date.Add(24*time.Hour))
+			if err != nil {
+				log.Printf("voice: calendar events: %v", err)
+				return "не получилось проверить календарь."
+			}
+			values := make([]string, len(events))
+			for i, e := range events {
+				values[i] = e.Value
+			}
+			var f router.CalendarEventFormatter
+			return f.Format(values, date)
+		}
+
 		vec, err := h.embedder.Embed(ctx, dec.Utterance)
 		if err != nil {
 			log.Printf("voice: embed query: %v", err)