Add JSDoc documentation and file headers to all source files

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/plugins/myPiniaPlugin.ts

@@ -1,5 +1,19 @@
+// The Lucia project.
+// Copyright 2023-2026 DSP, inc.  All rights reserved.
+// Authors:
+//   chiayin.kuo@dsp.im (chiayin), 2023/1/31
+//   imacat.yang@dsp.im (imacat), 2023/9/23
+//   cindy.chang@dsp.im (Cindy Chang), 2024/5/30
+/** @module myPiniaPlugin Custom Pinia plugin for store debugging. */
+
 import { PiniaPluginContext } from 'pinia';
 
+/**
+ * A Pinia plugin that logs all store mutations and state changes
+ * to the console for debugging purposes.
+ *
+ * @param {PiniaPluginContext} context - The Pinia plugin context.
+ */
 const myPiniaPlugin = (context: PiniaPluginContext) => {
   const { store } = context;