Add NFC chore submission feature and enhance family settings

- Introduced NFC support for chore submissions, allowing specific person credit after Head of Household approval.
- Updated family settings to include NFC base URL, scan cooldown, and confirmation page options.
- Enhanced chore management with options for anyone to complete chores and NFC link generation.
- Improved API endpoints for handling NFC tokens and chore submissions.
- Updated readme to reflect new NFC features and settings.

api/person_nfc_token_rotate.php

@@ -0,0 +1,46 @@
+<?php
+
+require_once __DIR__ . '/../includes/api_bootstrap.php';
+require_once __DIR__ . '/../includes/chore_helpers.php';
+
+if ($_SERVER['REQUEST_METHOD'] !== 'POST') {
+    sendJson(['success' => false, 'error' => 'Method not allowed'], 405);
+}
+
+$people = migrateAllPeople(normalizePeopleList(readJsonFile('people.json')));
+$actor = requireActivePerson($people);
+if (($actor['role'] ?? '') !== ROLE_HEAD || !isHohVerified()) {
+    sendJson(['success' => false, 'error' => 'Only a verified Head of household can rotate NFC person tokens'], 403);
+}
+
+$body = readJsonBody();
+$personId = isset($body['person_id']) ? trim((string) $body['person_id']) : '';
+if ($personId === '') {
+    sendJson(['success' => false, 'error' => 'person_id is required'], 400);
+}
+
+$match = null;
+foreach ($people as $i => $person) {
+    if (($person['id'] ?? '') === $personId) {
+        $match = $i;
+        break;
+    }
+}
+if ($match === null) {
+    sendJson(['success' => false, 'error' => 'Person not found'], 404);
+}
+
+$token = generateOpaqueToken();
+$people[$match]['nfc_submit_token_hash'] = hashOpaqueToken($token);
+$people[$match]['nfc_submit_token_updated_at'] = gmdate('c');
+
+if (!writeJsonFile('people.json', $people)) {
+    sendJson(['success' => false, 'error' => 'Failed to save person token'], 500);
+}
+
+sendJson([
+    'success' => true,
+    'person_id' => $personId,
+    'person_name' => (string) ($people[$match]['name'] ?? $personId),
+    'person_token' => $token,
+]);