Reduce default 2-player map size from 60x60 to 40x40 (from 3600 to 1600
tiles) to increase encounter frequency and combat density. Add -skirmish
flag to acb-mapgen for generating even smaller dense maps (32x32, 0.20
wall density, 15 energy nodes) with "skirmish_" ID prefix.
Changes:
- engine/types.go: DefaultConfig() returns 40x40, ConfigForPlayers()
uses 800 tiles/player for 2-player (40x40) and 2000 tiles/player for
3+ players
- cmd/acb-matchmaker/tickers.go: gridForPlayers() returns 40x40 for 2
players
- cmd/acb-map-evolver/main.go: gridForPlayers() returns 40x40 for 2
players
- cmd/acb-mapgen/main.go: defaults to 40x40, adds -skirmish flag for
32x32 high-density maps
- cmd/acb-matchmaker/tickers_test.go: update test expectations for new
40x40 default
Closes: bf-39wt
The bestCandidate function allowed game count to override pairing recency
when both candidates had non-zero LastPairedAt values. Per §6.1, pairing
recency must be the primary criterion with game count only breaking ties.
Also adds 10 tests covering: never-paired preference, oldest-pairing
preference, game count tiebreaking, Pareto distribution verification,
multi-opponent selection, and regression test for the priority inversion.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
