While a Tunnel Entry or Exit (building or construction site) is selected,
mark its connection green in the game world — the entry tile, exit tile,
and tiles between — reusing the tunnel_preview color from the placement
preview. Unpaired tunnels show no green.
- Add core findTunnelPartner(): the matching end of an existing tunnel
tile, reusing firstTunnelFacing so the pairing scan stays single-sourced;
unit-tested in TunnelCompletionTest.
- GameWorldView: extract the built+site tunnel index into
collectTunnelTiles() (shared with updateTunnelGhost) and add
drawSelectedTunnelConnections(), called from drawOverlays. Tiles are
deduped via a set so a connection selected from both ends fills once.
- Also commits the REQ-BLD-TUNNEL-SELECT-HIGHLIGHT requirement text.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Y7N59FsLA5e2kuVdqe4Uhc
Malte Langkabel
3ac3d8a6e6