Fix details pill border clipped thin at corners (#222)

The details pill drew its own 1px border with a 10px radius inside .float, which draws the real border at 20px radius and clips with overflow:hidden. The parent's looser curve clipped the pill's tighter corner curve, making the border appear thinner/cut at the corners, in both collapsed and expanded states. Drop the pill's own border/radius so .float is the single border surface, matching the other pills on the page.

Ref #222

internal/web/static/app.css

@@ -216,7 +216,10 @@ body {
 .tag { font-size: 19.8px; color: var(--muted-fg); border: 1px solid var(--border); border-radius: var(--radius-sm); padding: 2px 9px; }
 .paste-title-bar { display: flex; align-items: center; gap: 12px; padding: 12px 18px; flex-wrap: wrap; }
 .paste-title-bar h1 { font-size: 29.2px; font-weight: 600; margin: 0; word-break: normal; overflow-wrap: anywhere; }
-.stats-pill { border: 1px solid var(--border); border-radius: var(--radius); overflow: hidden; }
+/* #222: .float already draws the border + radius and clips corners; the pill's own
+   tighter border curve was getting clipped thin at the corners. Let .float be the
+   only border/paint surface for the details pill (collapsed and expanded). */
+.stats-pill { border: 0; border-radius: 0; overflow: hidden; }
 .stats-head { display: flex; align-items: center; gap: 16px; width: 100%; background: none; border: 0; border-bottom: 1px solid var(--border); color: var(--muted-fg); font: inherit; font-size: 21.6px; padding: 14px 18px; cursor: pointer; text-align: left; }
 .stats-head:hover { color: var(--fg); background: var(--surface-2); }
 .stats-chev { width: 18px; height: 18px; flex: none; transition: transform 0.15s ease; }