tune(battle-xp): raise defaults to XpPerWin=200 / XpPerLoss=50

Doubles the shipped defaults across all modes without touching per-mode
overrides. Curve interaction against classexp.csv (L1=50, L2=150):
- Win (200 XP): crosses both L1 + L2 → land at L3, Exp=0
- Loss (50 XP): exactly meets L1 → land at L2, Exp=0

Updates every affected test assertion (Practice, Rank, Free, TK2,
Colosseum, Story) for the new level/exp math.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

SVSim.Database/Models/Config/BattleXpConfig.cs

@@ -9,8 +9,8 @@ namespace SVSim.Database.Models.Config;
 [ConfigSection("BattleXp")]
 public class BattleXpConfig
 {
-    public int XpPerWin  { get; set; } = 100;
-    public int XpPerLoss { get; set; } = 25;
+    public int XpPerWin  { get; set; } = 200;
+    public int XpPerLoss { get; set; } = 50;
 
     public int? PracticeXpPerWin      { get; set; }
     public int? PracticeXpPerLoss     { get; set; }