router: let a habit question outrank the day plan, and know the weekend

IsDayPlanQuery fires on the token "планы" and its other-day list does not know
weekday names, so "какие у меня обычно планы по вторникам?" was claimed by the
day plan, which answered today's calendar stamped with today's date. The habit
source never ran. The matcher now declines any utterance ParseHabitQuery
claims, which keeps the decision out of the source table's ordering.

Two gaps in the same matcher. Sunday had only its dative plural listed, so "в
воскресенье" found no weekday. "по выходным" named days that no weekday word
matches, so it was answered with the whole-week profile. Both are recognised
now, and the weekend is read back as two days rather than pooled.

Found in review of #59.

internal/router/calendar.go

@@ -45,6 +45,15 @@ var otherDayWords = []string{
 // сегодня?" and a plan that hijacks every date-bearing question would bury the
 // events under checklist lines. Only a plan-shaped ask, and only about today.
 func IsDayPlanQuery(text string) bool {
+	// A habit question is never a day plan, whatever words it shares with one.
+	// "какие у меня обычно планы по вторникам?" carries "планы", so the plan
+	// source claimed it and answered today's calendar stamped with today's
+	// date, and the habit source never ran. Deciding it here rather than by
+	// reordering the source table keeps one matcher from depending on the
+	// other's position in a slice.
+	if _, ok := ParseHabitQuery(text); ok {
+		return false
+	}
 	toks := planTokens(text)
 	for _, t := range toks {
 		for _, w := range otherDayWords {