Add TOML tree-sitter language support

[possibilities]

Summary

• Add tree-sitter queries and language mapping for TOML (.toml)
• Captures table headers (bare, dotted, quoted) and array table headers
• Quoted table names are normalized (wrapping quotes stripped via _strip_wrapping_quotes helper)

Testing

pytest tests/test_toml_symbols.py tests/test_tree_sitter_languages.py tests/test_symbol_extraction_multilang.py -v