Fix /docs: add explicit route for openapi.yaml

Flask static folder wasn't serving .yaml files automatically.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

index.html

@@ -217,7 +217,7 @@
 			const emoteEl = document.getElementById("emote");
 			const messageEl = document.getElementById("message");
 			const POLL_INTERVAL = 2000;
-			const VERSION = "v1.3.2";
+			const VERSION = "v1.3.3";
 
 			// Sound system
 			let audioCtx = null;