Add /contacts and /calendar pages; email signature settings; v1.1.12

- /contacts: standalone page with hybrid contact list (submissions + manual entry), inline edit, search, archive
- /calendar: monthly release scheduling calendar reading/writing podcast checklist episode dates
- /email settings: editable signature panel; signature persisted server-side and injected into outgoing emails
- Move contacts out of /admin panel (now links to /contacts route)
- Partial PATCH for contact submissions (name, notes, archived independently)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/App.tsx

@@ -3,6 +3,8 @@ import type { ReactElement } from 'react'
 import { Link, NavLink, Routes, Route, useLocation, useNavigate, useParams } from 'react-router-dom'
 import AdminPage from './AdminPage'
 import EmailShell from './EmailPage'
+import ContactsShell from './ContactsPage'
+import CalendarShell from './CalendarPage'
 import QASection from './components/QASection'
 import ContactForm from './components/ContactForm'
 import { ColossiansStudyIndexPage, ColossiansStudyNotesPage, ColossiansStudySectionPage, StudyLandingPage, StudySignupPage, StudyAccountPage, StudyCommunityPage, StudyQuizPage } from './colossiansStudy'
@@ -2496,6 +2498,8 @@ export default function App() {
       <Route path="/certificate/:token" element={<PublicCertificatePage />} />
       <Route path="/admin" element={<AdminShell content={content} onSave={setContent} />} />
       <Route path="/email" element={<EmailShell />} />
+      <Route path="/contacts" element={<ContactsShell />} />
+      <Route path="/calendar" element={<CalendarShell />} />
       <Route path="/preview" element={<PreviewPage />} />
       <Route
         path="/privacy"