Verlauf aufgeraeumt + vollstaendiger README-Screenshot

- Verlauf zeigt nur abgehakte Saetze (nicht gemachte werden nicht mehr
  uebernommen); keine ✓/□-Boxen mehr, Uebungsname ohne Tages-Praefix,
  Saetze kompakt in einer Zeile -> deutlich weniger Text
- assets/screenshot.png neu: vollstaendige Session (alle Uebungen mit
  Werten) statt halb-leerer Ansicht
- Tests: 170 Checks gruen (40+18+52+32+28)

app.js

@@ -1297,25 +1297,17 @@ function renderSetSummary(s, a) {
   const byEx = {};
   for (const e of s.entries || []) (byEx[e.exercise] = byEx[e.exercise] || []).push(e);
   for (const exKey of Object.keys(byEx)) {
-    const li = el("li", "hist-entry");
     const sorted = byEx[exKey].sort((x, y) => x.sort - y.sort)
-      .filter(e => e.weight || e.reps);
+      .filter(e => e.done);
     if (!sorted.length) continue;
-    li.appendChild(el("span", "ex-name", exKey + ": "));
+    const li = el("li", "hist-entry");
+    const name = exKey.includes("/")
+      ? exKey.split("/").slice(1).join("/") : exKey;
+    li.appendChild(el("span", "ex-name", name + ": "));
     const setsWrap = el("span", "hist-sets");
-    sorted.forEach((e, idx) => {
-      const w = e.weight || t("empty_label");
-      const r = e.reps || t("empty_label");
-      const span = el("span", "hist-set");
-      span.appendChild(el("span", e.done ? "set-done-box" : "set-undone-box",
-        e.done ? "✓" : "□"));
-      span.appendChild(document.createTextNode(
-        w + " " + unit + " × " + r + " " + repsUnit));
-      setsWrap.appendChild(span);
-      if (idx < sorted.length - 1) {
-        setsWrap.appendChild(document.createTextNode("  ·  "));
-      }
-    });
+    setsWrap.textContent = sorted.map(e =>
+      (e.weight || t("empty_label")) + " " + unit + " × "
+      + (e.reps || t("empty_label")) + " " + repsUnit).join("  ·  ");
     li.appendChild(setsWrap);
     ul.appendChild(li);
   }