Add JSDoc documentation and file headers to all source files

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

cypress.config.js

@@ -1,4 +1,16 @@
 /* eslint-env node */
+// The Lucia project.
+// Copyright 2023-2026 DSP, inc.  All rights reserved.
+// Authors:
+//   chiayin.kuo@dsp.im (chiayin), 2023/1/31
+//   cindy.chang@dsp.im (Cindy Chang), 2024/8/12
+//   imacat.yang@dsp.im (imacat), 2026/3/5
+/**
+ * @module cypress.config
+ *   Cypress E2E test configuration with viewport
+ *   settings and base URL.
+ */
+
 const { defineConfig } = require("cypress");
 
 module.exports = defineConfig({