Split server/index.js into one file per area

Routes move to server/routes/ (auth, account, projects, reader, sharing, admin);
index.js keeps setup only. A smoke test walks 90 API calls against the real
server and compares every status with the pre-split behaviour.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

server/userPayload.js

@@ -0,0 +1,16 @@
+import { isAdminEmail } from './auth.js';
+import { votdAvailable } from './votd.js';
+import { listPasskeys } from './db.js';
+
+// Shape returned to the client for the signed-in user (login, MFA verify, /auth/me).
+export function userPayload(user) {
+  return {
+    id: user.id, email: user.email, totpEnabled: user.totpEnabled, podcastName: user.podcastName ?? null,
+    isAdmin: isAdminEmail(user.email),
+    reminderEnabled: user.reminderEnabled, ntfyUrl: user.ntfyUrl ?? null, ntfyTopic: user.ntfyTopic ?? null,
+    reminderTime: user.reminderTime ?? null,
+    votdEnabled: !!user.votdEnabled, votdTime: user.votdTime ?? null, votdAvailable: votdAvailable(),
+    prayerEnabled: !!user.prayerEnabled, prayerTime: user.prayerTime ?? null,
+    loginAlerts: !!user.loginAlerts, passkeyCount: listPasskeys(user.id).length,
+  };
+}