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>

server/state.js

@@ -90,6 +90,9 @@ export const state = {
   qrScans: [],
   qrCodesWritePromise: Promise.resolve(),
 
+  emailSettings: { signature: 'Grace and peace,\nVerse by Verse with Nate' },
+  emailSettingsWritePromise: Promise.resolve(),
+
   lastBackupStatus: { ok: true, at: null, error: null, file: null },
   lastCachePurgeStatus: { ok: true, at: null, error: null },
   lastDeployHookStatus: { ok: true, at: null, error: null },