docs: add jsdoc comments

lib/index.js

@@ -1,3 +1,44 @@
+/**
+ * @typedef {Object} Log
+ * @property {number} [id]
+ * @property {string} hostname
+ * @property {number} pid
+ * @property {string} source
+ * @property {Date} timestamp
+ * @property {string} level
+ * @property {string} message
+ * @property {string} [meta]
+ */
+
+/**
+ * @typedef {Object} LogFilter
+ * @property {string} [hostname]
+ * @property {number} [pid]
+ * @property {{source: string, level: string}[]} [level_json]
+ * @property {string[]} [sources]
+ * @property {string[]} [levels]
+ * @property {number} [lt_id]
+ * @property {number} [gt_id]
+ * @property {Date} [lte_timestamp]
+ * @property {Date} [gte_timestamp]
+ * @property {number} [limit=100]
+ */
+
+/**
+ * @typedef {Object} Config
+ * @property {number} id
+ * @property {string} key
+ * @property {string} value
+ */
+
+/**
+ * @typedef {Object} User
+ * @property {number} id
+ * @property {string} name
+ * @property {string} email
+ * @property {string} role
+ */
+
 const bcrypt = require('bcryptjs');
 const { EventEmitter } = require('events');
 const cron = require('node-cron');