Episode grid: move names out of the button into the tooltip

The visible names made the grid uneven (long titles wrapped to 2-3
lines). Buttons now show only the E-number; the full name lives in
the title attribute (hover tooltip: 'E1 — Ryomen Sukuna'). Dropped
the now-unused .ep-name CSS.

static/app.js

@@ -685,7 +685,6 @@ function renderEps() {
     const b = el("button", "ep" + (e.filler ? " filler" : ""));
     const done = watchDone.has(String(e.id));
     b.textContent = done ? "E" + e.number + " \u2713" : "E" + e.number;
-    if (e.name) b.append(el("span", "ep-name", e.name));
     b.title = `E${e.number}${e.name ? " — " + e.name : ""}`;
     if (done) b.classList.add("done");
     const pct = epProg.get(String(e.id));