Add agent feedback to create-next-app defaults (#99119)
## Summary
- include experimental agent feedback in the interactive recommended
defaults
- ask about agent feedback only when someone chooses a non-default
interactive setup, with **Yes** selected by default
- generate `experimental.agentFeedback: true` when enabled and support
explicit `--agent-feedback` and `--no-agent-feedback` flags
- keep CI, `--yes`, and other non-interactive flows opted out unless
`--agent-feedback` is provided
- document and test the recommended and customized setup flows
## CLI experience
Choosing the recommended defaults enables agent feedback without another
prompt:
```text
? Would you like to use the recommended Next.js defaults?
❯ Yes, use recommended defaults - TypeScript, ESLint, No React Compiler, Tailwind CSS, No src/ directory, App Router, No Cache Components, AGENTS.md, Agent feedback
No, customize settings - Choose your own preferences
```
Choosing a non-default setup asks:
```text
? Would you like to help improve Next.js by letting agents prepare anonymized feedback for your review as you code? (Disable anytime with `experimental.agentFeedback: false`.) › No / Yes
```
**Yes** is selected by default.
## Verification
- `pnpm --filter=create-next-app build`
- `HEADLESS=true pnpm --config.minimum-release-age=0 test-start-turbo
test/production/create-next-app/prompts.test.ts -t "should use
recommended defaults|should show reuse previous settings|should not
prompt user for choice and use defaults if --yes is defined"`
- `HEADLESS=true pnpm --config.minimum-release-age=0 test-start-turbo
test/production/create-next-app/index.test.ts -t "should list both agent
feedback flags in help|should enable agent feedback with
--agent-feedback|should not print assumed defaults when all flags are
provided"`
- Next.js watch build and type checking completed with no errors
- Prettier and ESLint passed
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