[boyfeiyu]

Fixes #63.

Add table_environment="tabular" to LatexTableWriter, including a writable property and factory keyword support. The default remains array, and LatexMatrixWriter keeps its existing output.

Tabular cells escape text before applying styles, preserve multiword headers, and use \ensuremath for infinities and whole-cell mathematical control words such as \alpha. Other expressions are literal text. The documentation and executable example describe usage and the existing style dependencies.

Validation on CPython 3.12 / macOS arm64:

• Full test suite: 1545 passed, 72 xfailed.
• Eight generated documents compiled with Tectonic, including text escaping, math cells, 24 style combinations, style filters, and array/matrix controls.
• Example and git diff --check passed.

The full Python/OS CI matrix and general Unicode font coverage have not been run locally.