fix(compact): size the window to the strip instead of a tuned constant

compactH was 158px, "tuned so the compact entry strip fits in a single row".
A constant tuned against a layout stops being true the moment the layout
changes, and this one outlived a strip that had since shrunk — leaving about
70px of empty window under the fields.

The frontend now measures what it rendered and asks for that height, watched by
a ResizeObserver so a strip that wraps at a narrow width is followed too. The
topbar is added as its declared h-8 rather than measured, since it is fixed.

Bounded in the backend: a measurement of zero — a layout not yet painted —
must not collapse the window, and the call is ignored unless compact is on so
nothing can shrink the normal window. Rounded to whole pixels so a sub-pixel
reflow cannot start a resize loop.

app.go

@@ -17774,3 +17774,29 @@ func (a *App) SetSpotTTLMinutes(min int) error {
 	a.setSetting(keyClusterSpotTTL, strconv.Itoa(min))
 	return nil
 }
+
+// SetCompactHeight resizes the compact window to fit its content.
+//
+// The height used to be a constant "tuned so the compact entry strip fits in a
+// single row". Constants tuned against a layout stop being true the moment the
+// layout changes, and this one outlived a strip that had since lost a row —
+// leaving a band of empty window under the fields. The frontend measures what
+// it actually rendered and says so.
+//
+// Ignored unless compact is on, so nothing can shrink the normal window.
+func (a *App) SetCompactHeight(h int) {
+	if a.ctx == nil || !a.compact {
+		return
+	}
+	// Bounded: a measurement of zero (a layout not yet painted) must not collapse
+	// the window to nothing, and no strip is ever 600px tall.
+	if h < 80 || h > 600 {
+		return
+	}
+	w, _ := wruntime.WindowGetSize(a.ctx)
+	if w <= 0 {
+		w = compactW
+	}
+	wruntime.WindowSetMinSize(a.ctx, 900, h)
+	wruntime.WindowSetSize(a.ctx, w, h)
+}