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>

src/router.ts

@@ -0,0 +1,56 @@
+import { getState, setDate, setSelectedHour, subscribe } from './app-state';
+import { HOUR_IDS, type HourId } from './hours/types';
+
+// Real paths (reground.org/vu/2026-08-09/prime), not hash routing — the
+// container's Caddy does SPA fallback via try_files, so there's no need to
+// avoid a rewrite rule the way a bare static docroot would have.
+const BASE = import.meta.env.BASE_URL;
+
+function isHourId(value: string): value is HourId {
+  return (HOUR_IDS as readonly string[]).includes(value);
+}
+
+function parseLocation(): { date?: string; hour?: HourId } {
+  const path = window.location.pathname;
+  if (!path.startsWith(BASE)) return {};
+  const [date, hour] = path.slice(BASE.length).split('/').filter(Boolean);
+  return {
+    date: date && /^\d{4}-\d{2}-\d{2}$/.test(date) ? date : undefined,
+    hour: hour && isHourId(hour) ? hour : undefined,
+  };
+}
+
+function urlFor(date: string, hour: HourId): string {
+  return `${BASE}${date}/${hour}`;
+}
+
+let lastUrl = '';
+
+function pushUrl(): void {
+  const { date, selectedHour } = getState();
+  const url = urlFor(date, selectedHour);
+  if (url === lastUrl) return;
+  lastUrl = url;
+  window.history.pushState(null, '', url);
+}
+
+export function initRouter(): void {
+  const { date, hour } = parseLocation();
+  if (date) setDate(date);
+  if (hour) setSelectedHour(hour);
+
+  const { date: currentDate, selectedHour } = getState();
+  lastUrl = urlFor(currentDate, selectedHour);
+  window.history.replaceState(null, '', lastUrl);
+
+  subscribe(() => pushUrl());
+
+  window.addEventListener('popstate', () => {
+    const parsed = parseLocation();
+    // Set lastUrl first so the notify() inside setDate/setSelectedHour below
+    // doesn't turn this back-navigation into a new forward pushState.
+    lastUrl = window.location.pathname;
+    if (parsed.date) setDate(parsed.date);
+    if (parsed.hour) setSelectedHour(parsed.hour);
+  });
+}