feat(ai): add per-character AI model assignment and identity profiles

Implements deterministic model resolution (column → env map → pool →
default) and adds AI identity fields to characters. Migration backfills
existing rows with deterministic defaults. Controller uses resolved model
and identity block in system prompts for contextual conversations.

app/Models/Character.php

@@ -17,7 +17,8 @@ use Illuminate\Database\Eloquent\Relations\HasMany;
  * ticker mutates needs and job progress continuously while nobody is online.
  */
 #[Fillable([
-    'user_id', 'city_id', 'name', 'skin', 'hair', 'shirt',
+    'user_id', 'city_id', 'name', 'ai_model', 'ai_age', 'ai_gender',
+    'ai_personality', 'ai_bio', 'skin', 'hair', 'shirt',
     'pos_x', 'pos_y', 'pos_z', 'money', 'energy', 'hunger', 'thirst', 'health',
     'state', 'job_id', 'house_id', 'education', 'exercise_count', 'is_online', 'last_tick_at',
     'hospitalized_until', 'face', 'beard', 'accessory', 'ride_kind', 'ride_until',
@@ -27,6 +28,20 @@ class Character extends Model
     /** @use HasFactory<CharacterFactory, $this> */
     use HasFactory;
 
+    /**
+     * Default personality pool for characters created without one.
+     *
+     * @var list<string>
+     */
+    public const AI_PERSONALITIES = [
+        'Extrovertido e curioso, adora puxar conversa com quem passa.',
+        'Tranquilo e observador, fala pouco mas escuta tudo com atenção.',
+        'Bem-humorado e espirituoso, brinca com todo mundo por perto.',
+        'Sério e direto, vai ao ponto sem rodeios.',
+        'Gentil e prestativo, sempre oferece ajuda antes de perguntarem.',
+        'Aventureiro e barulhento, vive contando histórias da cidade.',
+    ];
+
     public const STATE_AWAKE = 'awake';
 
     public const STATE_SLEEPING = 'sleeping';
@@ -176,6 +191,8 @@ class Character extends Model
             'user_id' => $user->id,
             'city_id' => $city->id,
             'name' => $firstName,
+            'ai_age' => random_int(18, 68),
+            'ai_personality' => self::AI_PERSONALITIES[array_rand(self::AI_PERSONALITIES)],
             'skin' => random_int(1, 4),
             'hair' => random_int(1, 4),
             'shirt' => random_int(1, 5),
@@ -220,6 +237,7 @@ class Character extends Model
     protected function casts(): array
     {
         return [
+            'ai_age' => 'integer',
             'pos_x' => 'float',
             'pos_y' => 'float',
             'pos_z' => 'float',