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/store/store_test.go

@@ -334,4 +334,47 @@ func TestPresenceStateSingletonRoundtrip(t *testing.T) {
 	if b, score, _, err := s.LoadPresenceState(ctx); err != nil || b != Present || score != 0.83 {
 		t.Fatalf("after save: want Present/0.83, got %s/%f (%v)", b, score, err)
 	}
+}
+
+func TestCalendarEvents(t *testing.T) {
+	store := newTestStore(t)
+	defer store.Close()
+
+	ctx := context.Background()
+	now := time.Date(2026, 7, 6, 12, 0, 0, 0, time.UTC)
+
+	// Write facts for different dates
+	store.WriteFact(ctx, time.Date(2026, 7, 6, 8, 0, 0, 0, time.UTC), KindSelf, "calendar_event_20260706_Morning-standup", `"Morning standup @ 10:00-10:30"`, "poll:caldav", 1.0, sql.NullInt64{})
+	store.WriteFact(ctx, time.Date(2026, 7, 6, 8, 0, 0, 0, time.UTC), KindSelf, "calendar_event_20260706_Lunch", `"Lunch @ 12:00-13:00"`, "poll:caldav", 1.0, sql.NullInt64{})
+	store.WriteFact(ctx, time.Date(2026, 7, 6, 8, 0, 0, 0, time.UTC), KindSelf, "calendar_event_20260707_Doctor", `"Doctor @ 14:00-15:00"`, "poll:caldav", 1.0, sql.NullInt64{})
+	store.WriteFact(ctx, time.Date(2026, 7, 6, 8, 0, 0, 0, time.UTC), KindSelf, "calendar_event_20260705_Yesterday", `"Yesterday thing"`, "poll:caldav", 1.0, sql.NullInt64{})
+
+	// Query July 6
+	events, err := store.CalendarEvents(ctx, now.Truncate(24*time.Hour), now.Truncate(24*time.Hour).Add(24*time.Hour))
+	if err != nil {
+		t.Fatalf("CalendarEvents: %v", err)
+	}
+	if len(events) != 2 {
+		t.Fatalf("expected 2 events on July 6, got %d", len(events))
+	}
+
+	// Query July 7
+	t7 := time.Date(2026, 7, 7, 0, 0, 0, 0, time.UTC)
+	events, err = store.CalendarEvents(ctx, t7, t7.Add(24*time.Hour))
+	if err != nil {
+		t.Fatalf("CalendarEvents: %v", err)
+	}
+	if len(events) != 1 {
+		t.Fatalf("expected 1 event on July 7, got %d", len(events))
+	}
+
+	// Query date with no events
+	t8 := time.Date(2026, 7, 8, 0, 0, 0, 0, time.UTC)
+	events, err = store.CalendarEvents(ctx, t8, t8.Add(24*time.Hour))
+	if err != nil {
+		t.Fatalf("CalendarEvents: %v", err)
+	}
+	if len(events) != 0 {
+		t.Fatalf("expected 0 events on July 8, got %d", len(events))
+	}
 }