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>

internal/ipc/server.go

@@ -107,6 +107,18 @@ func (a *storeAPI) RecentFacts(ctx context.Context, n int) ([]Fact, error) {
 	return out, nil
 }
 
+func (a *storeAPI) CalendarEvents(ctx context.Context, from, to time.Time) ([]Fact, error) {
+	fs, err := a.s.CalendarEvents(ctx, from, to)
+	if err != nil {
+		return nil, mapErr(err)
+	}
+	out := make([]Fact, len(fs))
+	for i, f := range fs {
+		out[i] = toFact(f)
+	}
+	return out, nil
+}
+
 func (a *storeAPI) RecentNudges(ctx context.Context, n int) ([]Nudge, error) {
 	ns, err := a.s.RecentNudges(ctx, n)
 	if err != nil {
@@ -520,6 +532,20 @@ func (s *Server) dispatch(ctx context.Context, req Request) (json.RawMessage, er
 		}
 		return marshalResult(out), nil
 
+	case MethodCalendarEvents:
+		var p calendarEventsReq
+		if err := unmarshalParams(req.Params, &p); err != nil {
+			return nil, err
+		}
+		out, err := s.api.CalendarEvents(ctx, p.From, p.To)
+		if err != nil {
+			return nil, err
+		}
+		if out == nil {
+			out = []Fact{}
+		}
+		return marshalResult(out), nil
+
 	case MethodRecentNudges:
 		var p nReq
 		if err := unmarshalParams(req.Params, &p); err != nil {