Add JSDoc documentation and file headers to all source files

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

index.html

@@ -1,3 +1,10 @@
+<!-- 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), 2024/7/9
+
+     Application entry point HTML template. -->
 <!DOCTYPE html>
 <html lang="en">
   <head>