fix: correct nerve fields placement in Character $fillable array

Nerve fields should be positioned after 'max_energy' per spec, not after 'max_health'.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/Models/Character.php

@@ -51,11 +51,11 @@ class Character extends Model
         'bank',
         'energy',
         'max_energy',
-        'health',
-        'max_health',
         'nerve',
         'max_nerve',
         'nerve_regen_at',
+        'health',
+        'max_health',
         'strength',
         'defense',
         'speed',