docs: add the demo video link (README + the app's Watch-the-demo button)

README.md

@@ -26,7 +26,7 @@ tags:
 
 **Try it live:** https://huggingface.co/spaces/build-small-hackathon/iris (open on a phone)
 **How it was built (agent trace):** https://huggingface.co/datasets/build-small-hackathon/iris-agent-trace
-**Demo video:** _‹add link›_ · **Social post:** _‹add link›_
+**Demo video:** https://youtu.be/h4AJOWuDCVc · **Social post:** _‹add link›_
 
 Iris is a voice-first assistant for blind and low-vision people. Open it on a phone,
 point the camera, and it tells you what's around you, out loud, in your language.

frontend/app.js

@@ -187,7 +187,7 @@ function resetSoon() { setTimeout(() => { resumeSR(); if (!busy) setState("", t(
 player.addEventListener("ended", () => { setTimeout(resumeSR, 700); if (!busy) setState("", t("idle")); });
 
 // ---- welcome popup (shown on every open): pitch read aloud, closeable by voice/tap ----
-const DEMO_VIDEO_URL = "https://huggingface.co/spaces/build-small-hackathon/iris";   // placeholder, swap for the demo video
+const DEMO_VIDEO_URL = "https://youtu.be/h4AJOWuDCVc";   // demo video
 let introOpen = true, autoCloseTimer = null, introRecog = null, introSpokenSession = false;
 try { introSpokenSession = sessionStorage.getItem("iris_introSpoken") === "1"; } catch (e) {}
 const CLOSE_WORDS = /\b(close|fechar|ok|okay|start|begin|continue|continuar|comecar|entendi|pode fechar|got it)\b/i;

frontend/index.html

@@ -77,7 +77,7 @@
         <button id="intro-en" class="intro-lang">EN</button>
         <button id="intro-pt" class="intro-lang">PT</button>
       </div>
-      <a id="intro-video" class="intro-video" href="https://huggingface.co/spaces/build-small-hackathon/iris" target="_blank" rel="noopener">Watch the demo</a>
+      <a id="intro-video" class="intro-video" href="https://youtu.be/h4AJOWuDCVc" target="_blank" rel="noopener">Watch the demo</a>
       <button id="intro-close" class="intro-close">Close</button>
       <p id="intro-hint" class="intro-hint">Say "close" or tap the button</p>
     </div>