Function parse_file 

pub fn parse_file(
    path: impl AsRef<Path>,
    component_defs: &ComponentDefs,
) -> Result<ParseResult, Vec<ParseError>>

Parse a single spec file into a ParseResult.

Implements the full parsing pipeline:

1. Preprocess (UTF-8 decode, BOM strip, CRLF normalize).
2. Front matter extraction and deserialization.
3. Markdown fence extraction (supersigil-xml).
4. XML parsing and component extraction.
5. Lint-time validation.

Stage 1 fatal errors prevent later stages. XML parse errors in one fence do not prevent other fences from being parsed.

Errors

Returns Vec<ParseError> containing all detected errors across stages.