[Registrar] Rewrite transfer page and add registration limits troubleshooting (cloudflare#28780)

* [Registrar] Rewrite transfer page and add registration limits troubleshooting

Restructure the transfer-domain-to-cloudflare page into two clear phases
(add domain to Cloudflare, then transfer registration) instead of the
previous flat 10-step list. Inline partials, add DNSSEC/nameserver
provider links, explain why each step is needed, and add registration
limits content with actionable guidance.

Add new troubleshooting section for transfers rejected due to
registration period limits (10-year max for most TLDs, 5-year for .co).
Clarify vague language throughout: specific WHOIS status explanations,
concrete 45-day expiration rule, ICANN contact-change lock details.

* [Registrar] Simplify transfer timeline language in opening paragraph

* [Registrar] Address PR review feedback and restore grace period transfer scenario

- Break opening paragraph into scannable bullet list (#1)
- Lead with action instead of comparison to other registrars (#2)
- Replace IDN jargon with plain language and example (#3)
- Lead with actionable advice in Restrictions block (#5)
- Cross-link 'active on Cloudflare' to full-setup docs (#6)
- Replace inlined DNSSEC links with dnssec-providers partial (#7)
- Slim 'Add your domain' section to cross-link full-setup page (#8)
- Reorder unlock section to put action before context (#9)
- Restore 45-day grace period scenario with concrete date example
  and ICANN refund entitlement, matching FAQ content (#10)

* [Registrar] Simplify transfer page, move details to troubleshooting

- Simplify opening: shorter total time bullet, one-line prereq
- Move Restrictions block content to troubleshooting page
- Move registration limits and 'domain not available' Details blocks
  to troubleshooting page as standalone sections with full examples
- Add 45-day grace period note in Before you begin with FAQ link
- Update TLD page to link to troubleshooting instead of removed anchor
- Simplify approve-transfer section for non-technical audience
- Convert caution to note for Active status requirement
- Make authoritative DNS requirement a bullet in Before you begin
- Remove redundant 'Go to Transfer Domains page' text (DashButton CTA)

* [Registrar] Restore auth code callout in opening note block

Author: mhsu