Append the default layouts block to a resume YAML document.
The layouts are taken from DEFAULT_RESUME_LAYOUTS and added to the
document as AST nodes, so the appended block always matches the canonical
default configuration without requiring another parse pass.
Parameters
doc: Document
The parsed resume YAML document.
Returns Document
The same document with the layouts block appended.
Append the default layouts block to a resume YAML document.
The layouts are taken from DEFAULT_RESUME_LAYOUTS and added to the document as AST nodes, so the appended block always matches the canonical default configuration without requiring another parse pass.