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/ui/shell.ts

@@ -0,0 +1,37 @@
+import { subscribe } from '../app-state';
+import { renderDayNav } from './day-nav';
+import { renderHourList } from './hour-list';
+import { renderHourView } from './hour-view';
+import { renderLanguageToggle } from './bilingual-toggle';
+
+export function mountShell(root: HTMLElement): void {
+  root.innerHTML = `
+    <header class="site-header">
+      <span class="site-title">vu</span>
+      <div data-slot="language-toggle"></div>
+    </header>
+    <div data-slot="day-nav"></div>
+    <main id="main" class="app-main">
+      <nav data-slot="hour-list" class="hour-list-nav" aria-label="Hours"></nav>
+      <div data-slot="hour-view" class="hour-view-region"></div>
+    </main>
+  `;
+
+  const dayNavEl = root.querySelector<HTMLElement>('[data-slot="day-nav"]');
+  const hourListEl = root.querySelector<HTMLElement>('[data-slot="hour-list"]');
+  const hourViewEl = root.querySelector<HTMLElement>('[data-slot="hour-view"]');
+  const languageToggleEl = root.querySelector<HTMLElement>('[data-slot="language-toggle"]');
+  if (!dayNavEl || !hourListEl || !hourViewEl || !languageToggleEl) {
+    throw new Error('shell markup is missing an expected slot');
+  }
+
+  function render(): void {
+    renderDayNav(dayNavEl!);
+    renderHourList(hourListEl!);
+    renderHourView(hourViewEl!);
+    renderLanguageToggle(languageToggleEl!);
+  }
+
+  render();
+  subscribe(render);
+}