Function parse_strict 

pub fn parse_strict(
    markdown: &str,
    limits: &ParseLimits,
) -> Result<NormalizedMarkdown, MarkdownParserError>

Strict parsing: bounded, lossless, and fail-closed.

Returns the normalized markdown with extracted blocks, or a typed error. A successful result never hides a parse error, a resource-limit violation, or silently dropped in-scope content (block extraction is validated).