fix(composite): recover from sixel encoder panics, clean up debug logging

The go-sixel library panics on certain image dimensions during Resize().
Added panic recovery in drawImage() that falls back to alt text display.
Cleaned up all debug logging from the investigation.

app/compositeview.go

@@ -252,6 +252,19 @@ func (cc *compositeContent) drawImage(ctx *ui.Context, idx, row, width, height i
 
 	vx := ctx.Window().Vx
 	graphic, ok := cc.graphics[idx]
+	// Recover from panics in vaxis image encoding (e.g. sixel encoder bugs)
+	defer func() {
+		if r := recover(); r != nil {
+			log.Errorf("composite: panic rendering image %d: %v", idx, r)
+			alt := "[image: render error]"
+			if idx < len(cc.images) && cc.images[idx].Alt != "" {
+				alt = fmt.Sprintf("[%s]", cc.images[idx].Alt)
+			}
+			if row >= 0 && row < ctx.Height() {
+				ctx.Printf(0, row, style, "%s", alt)
+			}
+		}
+	}()
 	if !ok {
 		var err error
 		graphic, err = vx.NewImage(img)