fix: preserve DOCX visual RTL table order

[developer0hye]

What changed

• detect enabled w:bidiVisual table properties from raw DOCX XML
• reverse RTL table rows and column widths during DOCX conversion
• remap column spans, vertical-merge indices, physical borders, and padding
• add real-world and asymmetric colspan regression coverage
• hydrate Git LFS fixtures in normal cross-platform test jobs so strict fixture assertions execute

Why

DOCX stores RTL table cells in logical order and uses w:bidiVisual to request right-to-left visual presentation. The converter ignored that property, so cells appeared in the opposite order from Microsoft Word.

Visual comparison

Microsoft Word GT	Before	After

Verification

• cargo test -p office2pdf --lib (1082 passed)
• cargo test -p office2pdf --test docx_fixtures (151 passed)
• cargo clippy -p office2pdf --lib --tests -- -D warnings
• CI: Linux, macOS, Windows, WASM, Clippy, format, DCO, and bulk fixtures passed
• AI visual inspection: after matches Word cell order (B1 | A1, B2 | A2); remaining offset is renderer margin/font metrics

Related: #195