* fix(doc): strip leading H1 duplicating --name on doc create
The doc platform renders the document name as the page title. When the
markdown body also opens with the same H1 — a habit LLM agents fall
into despite the skill docs saying otherwise — the created document
shows the title twice.
Strip a leading ATX H1 from the markdown body when its text equals the
document name (trimmed, case-insensitive), and print a stderr note so
agents learn the convention. Any other leading H1 is kept as
intentional content; names legitimately ending with '#' are not
over-trimmed. When the body is nothing but the duplicate H1, the
markdown param is omitted entirely.
* docs(skill): note the CLI auto-strip of a duplicate leading H1 in doc create
The convention stays the same (--name is the H1, body starts from ##),
but agents should recognize the new stderr note and not rely on the
fallback.