ChatBubbleDelegate Class

Detailed Description

Handles two rendering paths:

• Painted — simple content (plain text, markdown, images) is drawn directly by paint() using QTextDocument.
• Persistent editor — complex content (code blocks, task plan cards, error action buttons) gets a composite QWidget returned by createEditor().

Bubble chrome (background, border, role label, timestamp) is always painted by the delegate regardless of which content path is used.