Copy button on code blocks

Agents often hand over text that is meant to be pasted somewhere else as it is, such as a command or a message to send. They put it in a code block on the card. A code block now has a copy button in its corner. On the desktop it shows while the pointer is on the block; on the phone it is always there. One click copies the exact text. Code blocks also wrap now, so a long draft can be read in full before it goes out. Where the browser offers no clipboard, the button selects the text so a long press copies it.