Home: declutter (keep hero, board, heatmap)

- drop the history widget: the status board already groups the same
  shows by state; full list stays at ?history
- 6 stat cards + top-3 -> one muted line (watch time, eps, active
  days, streak, on hold) with 'see all ->' to ?stats
- section headers now small uppercase muted labels so the hero is
  the only loud element (page h2s unaffected)
- heatmap sits in a rounded card panel

static/style.css

@@ -56,7 +56,8 @@ h2 { margin: 0.4rem 0; }
 .grid.stats { grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); }
 .card.stat { padding: .8rem; gap: .2rem; }
 .stat-value { font-size: 1.3rem; font-weight: 700; }
-.heat-wrap { overflow-x: auto; margin: .5rem 0 .3rem; }
+.heat-wrap { overflow-x: auto; margin: .5rem 0 .3rem; background: var(--card);
+  border: 1px solid var(--bd); border-radius: 10px; padding: .7rem .8rem .5rem; }
 .heat-lbl { display: flex; gap: 3px; margin-bottom: 2px; }
 .heat-lbl .heat-lab { width: 14px; font-size: .65rem; color: var(--muted); white-space: nowrap; }
 .heat { display: flex; gap: 3px; }
@@ -139,6 +140,8 @@ button.tiny.on { border-color: var(--acc); color: var(--acc); }
 .crumb { display: inline-block; font-size: .85rem; color: var(--muted); margin-bottom: .2rem; }
 .crumb:hover { color: var(--acc); }
 .sec-head { display: flex; align-items: baseline; gap: .8rem; }
+.sec-head h2 { font-size: .95rem; font-weight: 600; text-transform: uppercase;
+  letter-spacing: .06em; color: var(--muted); margin: 1.2rem 0 .4rem; }
 .card.hist { position: relative; cursor: pointer; }
 .del { position: absolute; top: .35rem; right: .35rem; width: 1.5rem; height: 1.5rem;
   border-radius: 50%; border: 1px solid var(--bd); background: rgba(14, 15, 19, .8);