More reliable embedded interviews and code blocks

• More reliable embedded conversations: Consistent anonymous IDs across actions and resolved embed rendering mismatches.
• Auto-redirect on completion now defaults on: New returnUrl query parameter as a fallback completion redirect.
• Better code blocks: Line numbers, theme-aware syntax highlighting, and improved copy experience.
• Improved right-to-left language support: Direction-aware padding, list styles, and outline rendering.

Mobile layout fixes: prevented badge wrapping and kept action menus within card bounds.