feat(workspace): frameless console that blends into its card

The tab bar and terminal lose their bordered box: the bar keeps one
divider with an accent underline on the active tab, and the terminal is
painted in the card's colour (--surface-3) instead of the page's.

That made a long-standing overflow visible: xterm re-measures its cell
only on a font option change or a resize, so a webfont landing after
open left the fit on the fallback font's cell and the rows/cols spilled
out of the pane. Re-set the family and refit on document.fonts
loadingdone.

client/src/components/run/TerminalView.tsx

@@ -268,18 +268,31 @@ export function TerminalView({ runId, wsBaseUrl, onExit }: TerminalViewProps) {
     const reassert = () => sendSize();
     term.textarea?.addEventListener("focus", reassert);
 
-    const resizeObserver = new ResizeObserver(() => {
+    const refit = () => {
       // Never fit a collapsed console — see sendSize.
       const el = containerRef.current;
       if (!el || !el.clientWidth || !el.clientHeight) return;
       fit.fit(); // a real change fires onResize, which reports it
-    });
+    };
+    const resizeObserver = new ResizeObserver(refit);
     if (containerRef.current) resizeObserver.observe(containerRef.current);
+    // A webfont landing after open changes the cell, not the container, so the
+    // observer never fires — and xterm re-measures its cell only on a font
+    // option change or a resize, so the fit kept the fallback font's cell and
+    // the rows/cols overflowed the pane. Re-setting the family (a trailing
+    // space keeps it a change) makes xterm measure again before the fit.
+    const onFontLoaded = () => {
+      const family = term.options.fontFamily ?? "";
+      term.options.fontFamily = family.endsWith(" ") ? family.trimEnd() : `${family} `;
+      refit();
+    };
+    document.fonts?.addEventListener("loadingdone", onFontLoaded);
 
     return () => {
       disposed = true;
       if (retryTimer) clearTimeout(retryTimer);
       resizeObserver.disconnect();
+      document.fonts?.removeEventListener("loadingdone", onFontLoaded);
       term.textarea?.removeEventListener("focus", reassert);
       resizeDisposable.dispose();
       dataDisposable.dispose();