Adds explicit Terms of Service acceptance before Wrangler creates an anonymous temporary preview account via `--temporary`.

What changed:

- Prompts for explicit acceptance before creating a new anonymous preview account.
- Includes links to Cloudflare's Terms of Service and Privacy Policy in the prompt.
- Requires the user to type `yes`; any other input fails closed before provisioning.
- Handles non-interactive stdin, including piped input and empty/closed stdin.
- Skips the prompt when reusing an already-cached anonymous preview account.
- Keeps `--temporary` scoped to non-interactive auth fallback in this PR.
- Includes the interactive anonymous-auth behavior from #14093, now merged into this branch.
- Updates anonymous account provisioning to send the provisioning service's required TOS acceptance payload.
- Preserves environment-specific anonymous account caches and clears cached preview accounts on logout.

---

- Tests
  - [x] Tests included/updated
  - [ ] Automated tests not possible - manual testing has been completed as follows:
  - [ ] Additional testing not necessary because:
- Public documentation
  - [ ] Cloudflare docs PR(s): <!--e.g. <https://github.com/cloudflare/cloudflare-docs/pull/>...-->
  - [x] Documentation not necessary because: `--allow-anonymous` is a hidden Wrangler flag and the required legal URLs are included directly in the CLI prompt.

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