fix: replace @iarna/toml with smol-toml for TOML 1.0 and PEP 735 support

[TALLEC-Scott]

Fixes #207

Problem

@iarna/toml fails to parse mixed-type arrays (inline tables + strings) which is valid TOML 1.0 syntax used by PEP 735 dependency groups.

Error

[dependency-groups]
dev = [
{include-group = "test"}, # inline table
"ml_stack_document_extraction", # string
]

Results in:
TomlError: line 66, col 34
Config file "pyproject.toml" could not be parsed.

Solution

Replace @iarna/toml (unmaintained since 2019) with smol-toml - a modern, actively maintained TOML parser that correctly handles TOML 1.0 syntax.

Changes

• Replace @iarna/toml with smol-toml in dependencies
• Update imports and remove TOML.JsonMap type references

Testing

• Build successful
• All existing tests pass
• Correctly parses pyproject.toml with PEP 735 syntax