implement activity logging feature with UI for viewing logs

handlers/activity_log.php

@@ -0,0 +1,20 @@
+<?php
+
+/**
+ * Admin: read API activity log (app sync + data changes only).
+ */
+
+require_once __DIR__ . '/../lib/api_log.php';
+
+$tokenRec = require_valid_token_web();
+require_role(['admin'], $tokenRec);
+
+if ($method !== 'GET') {
+    json_error('METHOD_NOT_ALLOWED', 'Method not allowed', 405);
+}
+
+$date     = trim((string)($_GET['date'] ?? date('Y-m-d')));
+$activity = trim((string)($_GET['activity'] ?? ''));
+$limit    = (int)($_GET['limit'] ?? 200);
+
+json_success(qdb_api_log_read_entries($date, $activity, $limit));