Phase A (Python surface):
- New mcrfpy.Heuristic IntEnum: EUCLIDEAN, MANHATTAN, CHEBYSHEV, DIAGONAL, ZERO
- Grid.find_path() accepts heuristic= and weight= kwargs (weighted A*)
- Grid.get_dijkstra_map() accepts roots= (list of positions or DiscreteMap mask)
Phase B (FLEE primitives):
- DijkstraMap.invert() returns a new map with inverted distance field
- DijkstraMap.descent_step(pos) returns steepest-descent neighbor or None
DijkstraMap internally switched from the C++ TCODDijkstra wrapper to the C API
(TCOD_dijkstra_*) because multi-root compute and invert/get_descent are not
exposed on the wrapper. Single-root Dijkstra cache is preserved for backward
compatibility; multi-root and mask paths bypass the cache since cache keys
would be ill-defined.
New tests: heuristic_enum_test, find_path_heuristic_test, multi_root_dijkstra_test,
dijkstra_flee_test. Baseline JSONs for dijkstra_bench and gridview_render_bench
refreshed against the new implementation.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
