Milestone 0/1: shell, calendar/psalter/hours scaffold, Prime

Client-side-first PWA (Vite/TS, no backend) per the approved plan: day-
navigable shell listing all 8 hours, Prime fully resolves via the
calendar -> psalter -> ordo pipeline, the other 7 hours are registered
but flagged not-implemented. Sanctoral/temporal calendar data uses a
day -> id indirection layer (saints, easter-offsets, fixed-date-calendar)
so reassigning a feast to a different day is a data edit, not a code
change. Docker (Caddy-serving-static) + Gitea CI workflow scaffolded to
match the eec/drip/bookshop operational pattern.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

tests/calendar/weekday.test.ts

@@ -0,0 +1,40 @@
+import { describe, expect, it } from 'vitest';
+import { weekdayOf } from '../../src/calendar/weekday';
+import { resolveDay } from '../../src/calendar';
+
+describe('weekdayOf', () => {
+  it('resolves a known Sunday', () => {
+    // 2026-08-09 is a Sunday.
+    expect(weekdayOf('2026-08-09')).toBe('sunday');
+  });
+
+  it('resolves each day of a full week correctly', () => {
+    const expected = [
+      ['2026-08-09', 'sunday'],
+      ['2026-08-10', 'monday'],
+      ['2026-08-11', 'tuesday'],
+      ['2026-08-12', 'wednesday'],
+      ['2026-08-13', 'thursday'],
+      ['2026-08-14', 'friday'],
+      ['2026-08-15', 'saturday'],
+    ] as const;
+    for (const [date, weekday] of expected) {
+      expect(weekdayOf(date)).toBe(weekday);
+    }
+  });
+
+  it('is not affected by the local timezone offset', () => {
+    // Regression guard: resolving via `new Date(isoDate)` without pinning to
+    // UTC would give different weekdays depending on the host's timezone.
+    expect(weekdayOf('2026-01-01')).toBe('thursday');
+  });
+});
+
+describe('resolveDay', () => {
+  it('stubs season and occurring until milestone 4', () => {
+    const day = resolveDay('2026-08-09');
+    expect(day.date).toBe('2026-08-09');
+    expect(day.weekday).toBe('sunday');
+    expect(day.occurring).toEqual([]);
+  });
+});