naming: localise liturgical day names in any language

Add internal/naming, which renders temporal day names and celebration
display names from the calendar engine's slugs in any language. English is
the built-in baseline; a language is data -- an embedded lang/<code>.ini
(pl shipped) and/or a user file at <config dir>/names/<code>.ini that
overrides it key by key. Names compose from a small vocabulary plus
per-language format templates, so word order and grammatical case can
differ (e.g. Polish genitive "3. Niedziela Okresu Zwykłego"); any string a
language omits falls back to English.

- Move day-name generation out of calendar (calendar.HumanizeSlug removed,
  calendar stays a pure engine) into naming.DayName; the English golden
  cases carry over verbatim.
- naming.CelebrationName unifies the three duplicated resolvers
  (cli/readings/calfeed): name.<lang> -> English -> Latin -> humanized slug.
  Saint names stay in the calendar data (name.<lang>), overridable via
  calendar layers.
- config: ui_language now accepts any code (lower-cased, not clamped to
  en/pl) so names/<code>.ini applies; UI chrome still resolves en/pl and
  falls back to English. Add NamesDir(); wire naming.SetUserDir (and the
  previously unwired bible.SetUserCorporaDir) in the TUI and web mains too,
  so external corpora and name files work across all three binaries.

1 files changed, 55 insertions, 0 deletions

diff --git a/internal/naming/naming_test.go b/internal/naming/naming_test.go
new file mode 100644
index 0000000..a3bc49f
--- /dev/null
+++ b/internal/naming/naming_test.go
@@ -0,0 +1,55 @@
+package naming
+
+import "testing"
+
+// English must reproduce exactly what calendar.HumanizeSlug produced before the
+// name generation moved here (the golden cases carried over verbatim).
+func TestDayNameEnglish(t *testing.T) {
+	cases := map[string]string{
+		"ordinary-sunday-11":            "11th Sunday in Ordinary Time",
+		"ordinary-11-tue":               "Tuesday of the 11th Week in Ordinary Time",
+		"advent-2-mon":                  "Monday of the 2nd Week of Advent",
+		"advent-dec-17":                 "December 17",
+		"lent-after-ashes-wed":          "Ash Wednesday",
+		"lent-after-ashes-thu":          "Thursday after Ash Wednesday",
+		"triduum-fri":                   "Good Friday",
+		"easter-octave-mon":             "Monday in the Octave of Easter",
+		"christmas-jan-2":               "January 2",
+		"christmas-after-epiphany-mon":  "Monday after the Epiphany",
+		"trinity-sunday":                "The Most Holy Trinity",
+		"ef-time-after-pentecost-4-tue": "Tuesday of the 4th Week after Pentecost",
+		"ef-passiontide-0-thursday":     "Thursday of Passion Week",
+		"ef-september-ember-wed":        "Ember Wednesday of September",
+	}
+	for slug, want := range cases {
+		if got := DayName(slug, "en"); got != want {
+			t.Errorf("DayName(%q, en) = %q, want %q", slug, got, want)
+		}
+	}
+}
+
+// Polish must localise both named days and composed names, using its own word
+// order and genitive-case season names.
+func TestDayNamePolish(t *testing.T) {
+	cases := map[string]string{
+		"ordinary-sunday-11":            "11. Niedziela Okresu Zwykłego",
+		"ordinary-11-tue":               "Wtorek 11. tygodnia Okresu Zwykłego",
+		"advent-2-mon":                  "Poniedziałek 2. tygodnia Adwentu",
+		"advent-dec-17":                 "17 grudnia",
+		"triduum-fri":                   "Wielki Piątek",
+		"lent-after-ashes-wed":          "Środa Popielcowa",
+		"ef-time-after-pentecost-4-tue": "Wtorek 4. tygodnia po Zesłaniu Ducha Świętego",
+	}
+	for slug, want := range cases {
+		if got := DayName(slug, "pl"); got != want {
+			t.Errorf("DayName(%q, pl) = %q, want %q", slug, got, want)
+		}
+	}
+}
+
+// An unknown language falls back entirely to English.
+func TestDayNameUnknownLangFallsBackToEnglish(t *testing.T) {
+	if got := DayName("ordinary-sunday-3", "xx"); got != "3rd Sunday in Ordinary Time" {
+		t.Errorf("unknown lang = %q", got)
+	}
+}