Function parse_import_layout 

pub fn parse_import_layout(content: &str) -> ImportLayout

Parse the import layout of a Python source file.

Tries AST-based parsing first (via rustpython-parser); falls back to a simpler line-scan if the file has syntax errors (e.g. during active editing).

The returned ImportLayout contains:

• groups — classified contiguous import blocks with line ranges,
• from_imports / bare_imports — individual import statements,
• lines — the file lines (for TextEdit character-length lookups).