feat: add L1 Basic AI and L2 Rule AI with heuristic scoring

src/ai/base_ai.gd

@@ -0,0 +1,11 @@
+# src/ai/base_ai.gd
+class_name BaseAI
+extends RefCounted
+
+var ai_name: String = "AI"
+
+func decide(hand: Array, table: Array, current_rank: int, config: RuleConfig) -> HandEvaluator.EvaluatedPlay:
+    var pass := HandEvaluator.EvaluatedPlay.new()
+    pass.type = -1
+    pass.primary_rank = 0
+    return pass