docs: Remove bespoke AI prompts from documentation pages (#12167)
## Summary
- Removes the `<CopyPrompt>` component and all its usages from 27
documentation pages
- Deletes `apps/docs/components/copy-prompt.tsx`
These per-page AI prompts we believe to be an anti-pattern. As long as
we provided high-quality content and make it available to agents, then
there's no need for this. The page a user is already looking at _is_ the
prompt.