spec: AEO 1.1 draft — sitemap.md, section anchors, structured-data hints

[aagarwal1012]

Open the design discussion for AEO Spec v1.1. Three concrete extensions on the table:

1. sitemap.md — a markdown sibling to sitemap.xml carrying a flat list of canonical markdown twin URLs with last-modified + token-count.
2. Per-section anchors — a stable convention for naming H2/H3 anchors so AI tools can deep-link to a specific answer (page.md#faq-refunds).
3. Structured data hints — opt-in fenced blocks in markdown twins that mirror schema.org JSON-LD without the HTML tax.

Scope

• Draft spec/v1.1-draft.md covering the three above with RFC-2119 normative wording.
• Include a migration note: v1.0 conformance must remain valid.
• Open a discussion thread (or check the box on this issue) for feedback before merging.

Anti-scope

• No code changes in this issue. Spec only. Implementation lands in follow-ups, one per package.

Pointers

• spec/README.md, spec/discovery.md, spec/headers.md.