Bug 44: Split Button — Dropdown Arrow

WCAG 1.1.1 (Text Alternatives), 4.1.2 (Name, Role, Value) | Dropdown arrow button without accessible name.

Bug: Arrow Button No aria-label
Bug: Dropdown State Not Announced
Bug: Main Button Action Unclear
How HAL Fixes This: HAL detects split buttons and adds aria-label to the dropdown arrow (e.g., "Download options" or "More actions"). It also adds aria-expanded="true/false" to indicate menu state and aria-haspopup="menu" to indicate a menu will open.