Add long-press copy to Quick Actions input and output

[mcintyre94]

Summary

• Long-pressing the question text in Quick Chat copies it to the clipboard
• Long-pressing the response (markdown) in Quick Chat copies the raw markdown
• Long-pressing the command echo in Bash copies the command
• Long-pressing the output in Bash copies the output
• Extracted a shared .copyContextMenu() View extension in Extensions.swift to avoid repeating the pattern across all four sites

Consistent with the existing long-press copy behaviour on chat bubbles (AssistantMessageView, UserBubbleView).

Test plan

• Open Quick Actions sheet → Quick Chat tab, send a question, long-press the greyed-out question → Copy appears and copies correctly
• Long-press the markdown response → Copy appears and copies the raw markdown
• Switch to Bash tab, run a command, long-press the command echo → copies command (without > prefix)
• Long-press the output → copies output
• Verify no copy menu appears on the shimmer ("Thinking…" / "Running…") states
• Verify behaviour on iPad and Mac (right-click)

🤖 Generated with Claude Code

[claude]

Code review

No issues found. Checked for bugs and CLAUDE.md compliance.