Resolve a physical arrow key into its logical inline counterpart, honouring
the writing direction. Under rtl the physical ArrowLeft and ArrowRight
swap, so a dispatch site can route a physical key to the handler that owns
its logical intent (inline-forward / inline-back). Any other key - vertical
arrows, Home, End, letters - is returned verbatim.
Tier-2 semantic strategies (menu submenu open/close, tree expand/collapse)
resolve the key here at the dispatch site, so the strategy contract stays
logical and custom strategy overrides get RTL for free.