Adds renderRegionChain — for tier 4-5 multi-region zones, renders the
4-region progression (e.g. ST──DO──IW──TDT for Underdark) with ✓
cleared / ▶ here / · pending markers, and ⛺ overlay where a base
camp has been pitched. Single-region zones skip the chain and fall
through to the existing renderZoneMap room layout.
!map (top-level) and !expedition map both invoke handleExpeditionMapCmd
which composes: region chain → current region label → per-run room
map → legend. Region abbreviations are decoded in a "Regions:" footer
so the glyph row stays compact.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
