docs: drop duplicate page titles and stale migration link GitHub wiki renders the filename as the page title, so remove the leading H1 from each page. Replace the link to the removed migration page in the FAQ with a changelog link.
docs: add full wiki documentation for quill Add Home, sidebar and footer plus guides for getting started, core concepts, query building, reading and writing data, pagination, transactions, typed API, struct mapping, dialect differences, security, error reference, API overview, cookbook, FAQ, 0.2 migration and contributing.