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

tests/Feature/HospitalAdmissionTest.php

@@ -11,7 +11,7 @@ use Illuminate\Foundation\Testing\RefreshDatabase;
 use Tests\TestCase;
 
 /**
- * Traffic accident → hospital admission for two game days.
+ * Traffic accident → hospital admission for one game hour.
  */
 class HospitalAdmissionTest extends TestCase
 {
@@ -34,9 +34,9 @@ class HospitalAdmissionTest extends TestCase
     }
 
     /**
-     * A vehicle collision admits the character for two game days at the hospital.
+     * A vehicle collision admits the character for one game hour at the hospital.
      */
-    public function test_accident_admits_character_for_two_game_days(): void
+    public function test_accident_admits_character_for_one_game_hour(): void
     {
         $response = $this->postJson('/city/actions/accident');
         $response->assertOk()
@@ -51,7 +51,7 @@ class HospitalAdmissionTest extends TestCase
             $this->character->hospitalized_until->getTimestamp(),
             5,
         );
-        $this->assertSame(Character::HOSPITAL_STAY_SECONDS, 480, 'Two game days = 2 × 240s');
+        $this->assertSame(Character::HOSPITAL_STAY_SECONDS, 10, 'One game hour = 240s / 24');
 
         $hospital = Building::where('type', Building::TYPE_HOSPITAL)->firstOrFail();
         $this->assertSame((float) $hospital->pos_x, (float) $this->character->pos_x);
@@ -88,9 +88,9 @@ class HospitalAdmissionTest extends TestCase
     }
 
     /**
-     * After the two-day stay the ticker releases the character.
+     * After the one-hour stay the ticker releases the character.
      */
-    public function test_ticker_releases_after_two_game_days(): void
+    public function test_ticker_releases_after_one_game_hour(): void
     {
         $this->character->admitToHospital();
         // Move the stay into the past to simulate elapsed time.

tests/Feature/PlazaExerciseTest.php

@@ -0,0 +1,139 @@
+<?php
+
+namespace Tests\Feature;
+
+use App\Models\Character;
+use App\Models\User;
+use App\Support\CityPlazas;
+use Database\Seeders\CityWorldSeeder;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Tests\TestCase;
+
+/**
+ * Public plaza gym equipment and health gains from exercise.
+ */
+class PlazaExerciseTest extends TestCase
+{
+    use RefreshDatabase;
+
+    protected User $user;
+
+    protected Character $character;
+
+    /**
+     * Boot world fixtures.
+     */
+    protected function setUp(): void
+    {
+        parent::setUp();
+        $this->seed(CityWorldSeeder::class);
+        $this->user = User::factory()->create(['status' => User::STATUS_ACTIVE, 'is_active' => true]);
+        $this->character = Character::ensureForUser($this->user);
+        $this->actingAs($this->user);
+    }
+
+    /**
+     * City payload includes plazas with gym equipment.
+     */
+    public function test_city_data_includes_plazas(): void
+    {
+        $this->getJson('/city/data')
+            ->assertOk()
+            ->assertJsonStructure([
+                'plazas' => [
+                    ['id', 'position', 'size', 'equipment' => [['id', 'kind', 'position']]],
+                ],
+            ]);
+
+        $this->assertNotEmpty(CityPlazas::forCity($this->character->city));
+    }
+
+    /**
+     * Exercising near equipment raises health and increments the counter.
+     */
+    public function test_exercise_gains_health_near_equipment(): void
+    {
+        $eq = CityPlazas::forCity($this->character->city)[0]['equipment'][0];
+        $this->character->forceFill([
+            'pos_x' => $eq['position'][0],
+            'pos_z' => $eq['position'][1],
+            'health' => 80,
+            'energy' => 90,
+            'state' => Character::STATE_AWAKE,
+        ])->save();
+
+        $this->postJson('/city/actions/exercise', [
+            'pos_x' => $eq['position'][0],
+            'pos_z' => $eq['position'][1],
+        ])->assertOk()
+            ->assertJsonPath('character.health', 82)
+            ->assertJsonPath('character.state', Character::STATE_EXERCISING);
+
+        $this->character->refresh();
+        $this->assertSame(82, (int) $this->character->health);
+        $this->assertSame(1, (int) $this->character->exercise_count);
+        $this->assertSame(88, (int) $this->character->energy);
+    }
+
+    /**
+     * Far from equipment the action is rejected.
+     */
+    public function test_exercise_requires_nearby_equipment(): void
+    {
+        $eq = CityPlazas::forCity($this->character->city)[0]['equipment'][0];
+        $this->character->forceFill([
+            'pos_x' => $eq['position'][0] + 50,
+            'pos_z' => $eq['position'][1] + 50,
+            'health' => 50,
+        ])->save();
+
+        $this->postJson('/city/actions/exercise', [
+            'pos_x' => $eq['position'][0] + 50,
+            'pos_z' => $eq['position'][1] + 50,
+        ])->assertStatus(422);
+    }
+
+    /**
+     * Max health refuses further gains but keeps the character healthy.
+     */
+    public function test_exercise_stops_at_max_health(): void
+    {
+        $eq = CityPlazas::forCity($this->character->city)[0]['equipment'][0];
+        $this->character->forceFill([
+            'pos_x' => $eq['position'][0],
+            'pos_z' => $eq['position'][1],
+            'health' => 100,
+        ])->save();
+
+        $this->postJson('/city/actions/exercise', [
+            'pos_x' => $eq['position'][0],
+            'pos_z' => $eq['position'][1],
+        ])->assertOk()
+            ->assertJsonPath('character.health', 100);
+
+        $this->assertSame(0, (int) $this->character->fresh()->exercise_count);
+    }
+
+    /**
+     * stop-exercise returns the character to awake.
+     */
+    public function test_stop_exercise_returns_awake(): void
+    {
+        $eq = CityPlazas::forCity($this->character->city)[0]['equipment'][0];
+        $this->character->forceFill([
+            'pos_x' => $eq['position'][0],
+            'pos_z' => $eq['position'][1],
+            'health' => 70,
+            'state' => Character::STATE_AWAKE,
+        ])->save();
+
+        $this->postJson('/city/actions/exercise', [
+            'pos_x' => $eq['position'][0],
+            'pos_z' => $eq['position'][1],
+        ])->assertOk();
+
+        $this->postJson('/city/actions/stop-exercise')
+            ->assertOk()
+            ->assertJsonPath('character.state', Character::STATE_AWAKE);
+    }
+}