Split purchase budget based on investment ratio.

The AI purchaser will aim to have a 50/50 ground/air investment mix.
This allows it to overspend on one category if significant losses were
taken the previous turn.

The total purchase amount is still limited, so if the bases are full
when only 10% of the investment is in ground units, the full budget for
the turn will still go to air.

game/game.py

@@ -438,8 +438,8 @@ class Game:
         # gets much more of the budget that turn. Otherwise budget (after
         # repairs) is split evenly between air and ground. For the default
         # starting budget of 2000 this gives 600 to ground forces and 1400 to
-        # aircraft.
-        ground_portion = 0.3 if self.turn == 0 else 0.5
+        # aircraft. After that the budget will be spend proportionally based on how much is already invested
+
         self.budget = ProcurementAi(
             self,
             for_player=True,
@@ -447,7 +447,6 @@ class Game:
             manage_runways=self.settings.automate_runway_repair,
             manage_front_line=self.settings.automate_front_line_reinforcements,
             manage_aircraft=self.settings.automate_aircraft_reinforcements,
-            front_line_budget_share=ground_portion,
         ).spend_budget(self.budget)
 
         self.enemy_budget = ProcurementAi(
@@ -457,7 +456,6 @@ class Game:
             manage_runways=True,
             manage_front_line=True,
             manage_aircraft=True,
-            front_line_budget_share=ground_portion,
         ).spend_budget(self.enemy_budget)
 
     def message(self, text: str) -> None: