feat(city): add plaza exercise system with health tracking

- Adds CityPlazas support class for deterministic public plaza generation with outdoor gym equipment
- Implements exercise and stop-exercise actions with proximity validation to equipment
- Introduces health (0-100) and exercise_count attributes to Character model
- Reduces hospital stay duration from two game days to one game hour
- Adds 3D gym equipment rendering (bench, bars, bike, treadmill) in city viewer
- Includes exercise state machine handling in world ticker with energy drain
- Adds comprehensive PlazaExerciseTest and updates HospitalAdmissionTest
- Provides localized UI strings for health HUD and exercise prompts

database/migrations/2026_10_18_001000_add_hospitalized_until_to_characters_table.php

@@ -7,7 +7,7 @@ use Illuminate\Support\Facades\Schema;
 /**
  * Adds hospital admission tracking to characters.
  *
- * When a character is hit by a vehicle they are admitted for two game days
+ * When a character is hit by a vehicle they are admitted for one game hour
  * (hospitalized_until). The world ticker releases them automatically.
  */
 return new class extends Migration

database/migrations/2026_10_18_002000_add_health_to_characters_table.php

@@ -0,0 +1,35 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+/**
+ * Adds fitness tracking to characters.
+ *
+ * health is 0-100 and rises while the character exercises on public plaza
+ * equipment; exercise_count is a lifetime counter for progress display.
+ */
+return new class extends Migration
+{
+    /**
+     * Run the migrations.
+     */
+    public function up(): void
+    {
+        Schema::table('characters', function (Blueprint $table): void {
+            $table->unsignedTinyInteger('health')->default(100)->after('thirst');
+            $table->unsignedInteger('exercise_count')->default(0)->after('education');
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     */
+    public function down(): void
+    {
+        Schema::table('characters', function (Blueprint $table): void {
+            $table->dropColumn(['health', 'exercise_count']);
+        });
+    }
+};

database/seeders/CityWorldSeeder.php

@@ -56,7 +56,7 @@ class CityWorldSeeder extends Seeder
             ['salary' => 14, 'requires_education' => 60],
         );
 
-        // City hospital: accident victims are admitted here for two game days.
+        // City hospital: accident victims are admitted here for one game hour.
         Building::updateOrCreate(
             [
                 'city_id' => $city->id,
@@ -83,5 +83,9 @@ class CityWorldSeeder extends Seeder
         User::query()->where('status', User::STATUS_ACTIVE)->each(function (User $user) use ($city): void {
             Character::ensureForUser($user, $city);
         });
+
+        // Backfill fitness columns for characters created before the migration.
+        Character::query()->whereNull('health')->update(['health' => 100]);
+        Character::query()->whereNull('exercise_count')->update(['exercise_count' => 0]);
     }
 }