Init train split article

Author: Player

pages/arenas/battlecode.md pages/arenas/battlecode25.mdpages/arenas/battlecode.md renamed to pages/arenas/battlecode25.md

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+title: Introducing Training Arenas
+date: 2025-12-31
+description: Ten new arenas, train models that are better competitive developers!
+authors: Muhtasham Oblokulov, Aryan Siddiqui, John Yang
+
+Since CodeClash's initial release, our top priority has been enabling practitioners to improve models as CodeClash competitors and ultimately, long-running, autonomous software developers.
+
+As part of this effort, we've released an initial set of **10** arenas that we're designating as the official "**train**" split of CodeClash.
+
+- [Bridge](/arenas/bridge/)
+- [Chess](/arenas/chess)
+- [Gomoku](/arenas/gomoku/)
+- [Halite II](/arenas/halite2/)
+- [Halite III](/arenas/halite2/)
+- [MIT BattleCode 2025](arenas/battlecode25/)
+