Every road path search — highway, branch, county — now goes through one
function instead of three direct GetPointPath calls. The function body is
exactly the call it replaced, so behaviour is unchanged.
This exists so the next commit's pathfinding change can be judged on its own:
if the generated map changes after this point, it was the heuristic, not a
refactor slip.
Routing is untouched: which towns connect, loop order, Prim's daisy-chain,
tier assignment and the abandon protocol all deal only in town positions and
never touch the grid.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
