style: Add full doc comments to proxy.js, server.js, test.js, api/index.js

- Box-style header with project/author/license
- Section headers (═══ SECTION ═══)
- Function-level JSDoc (purpose, params, returns, examples)
- Inline notes for non-obvious logic
- Feature markers (---- FEATURE: XYZ ----)
- Footer on every module

api/index.js

@@ -1 +1,18 @@
+/*
+ * ======= • ======= • ======= • ======= • =======• =======
+ * MiruroAPI — api/index.js
+ * Repository: https://github.com/Shineii86/MiruroAPI
+ *
+ * @description
+ *   Vercel serverless function entry point.
+ *   Single line that re-exports the Express app from server.js.
+ *   Vercel maps all /api/* routes to this file.
+ *
+ * @author  Shinei Nouzen
+ * @license MIT
+ * ======= • ======= • ======= • ======= • =======• =======
+ */
+
 module.exports = require("../server");
+
+// ══════════════════════════════════════════════════════════════ END: api/index.js