autoplay first episode by default, resume watched

- no ?ep= param: resume last watched ep of the season from history,
  else start at ep 1 (verified in headless Chromium, no click needed)
- if the browser blocks autoplay (no user gesture yet), show a
  'click to play' overlay instead of a silent black screen

static/app.js

@@ -126,6 +126,14 @@ async function showAnime(slug_id, opts = {}) {
   if (opts.ep) {
     const cur = [...eps.children].find(b => +b.dataset.ep === opts.ep);
     if (cur) { markActive(cur); play(opts.ep, cur.dataset.no); }
+  } else {
+    // default: resume last watched ep of this season, else start at ep 1
+    const h = hist().find(x => x.slug_id === slug_id && x.season_id === seasonId);
+    const auto = h ? h.ep_id : +eps.querySelector(".ep")?.dataset.ep;
+    if (auto) {
+      const cur = [...eps.children].find(b => +b.dataset.ep === auto);
+      if (cur) { markActive(cur); play(auto, cur.dataset.no); }
+    }
   }
 
   if (detail.synopsis) main.append(el("p", "synopsis bottom", detail.synopsis));
@@ -164,6 +172,7 @@ async function play(ep_id, ep_no) {
     hls.loadSource("/stream/" + s.token);
     hls.attachMedia(v);
     v.onerror = () => showStreamError("media error: " + (v.error?.message || v.error?.code));
+    v.play().catch(() => showPlayOverlay(v)); // autoplay blocked (no user gesture) -> visible prompt
   } catch (e) {
     showStreamError(e.message);
   }
@@ -172,6 +181,12 @@ async function play(ep_id, ep_no) {
   document.title = `${detail.name} E${ep_no} — ani-web`;
 }
 
+function showPlayOverlay(v) {
+  const o = el("button", "play-overlay", "▶ click to play");
+  o.onclick = () => { v.play(); o.remove(); };
+  v.parentElement.append(o);
+}
+
 // ---------- boot ----------
 (async () => {
   const p = new URLSearchParams(location.search);