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

app/Http/Controllers/Web/CityActionController.php

@@ -9,6 +9,7 @@ use App\Models\City;
 use App\Models\InventoryItem;
 use App\Models\Job;
 use App\Models\Transaction;
+use App\Support\CityPlazas;
 use Illuminate\Http\JsonResponse;
 use Illuminate\Http\Request;
 use Illuminate\Support\Facades\DB;
@@ -97,14 +98,90 @@ class CityActionController extends Controller
             'sell' => $this->sell($request, $character),
             'build' => $this->build($request, $character),
             'apply-job' => $this->applyJob($request, $character),
+            'exercise' => $this->exercise($request, $character),
+            'stop-exercise' => $this->stopExercise($character),
             default => response()->json(['message' => __('city.action_unknown')], 422),
         };
     }
 
+    /**
+     * One exercise rep on nearby plaza gym equipment: +health, −energy.
+     *
+     * Optional pos_x/pos_z let the client report its live position so the
+     * proximity check does not wait for the throttled position sync.
+     */
+    private function exercise(Request $request, Character $character): JsonResponse
+    {
+        if ($character->state === Character::STATE_SLEEPING) {
+            return response()->json(['message' => __('city.exercise_need_awake')], 422);
+        }
+
+        $data = $request->validate([
+            'pos_x' => ['nullable', 'numeric'],
+            'pos_z' => ['nullable', 'numeric'],
+        ]);
+
+        $x = array_key_exists('pos_x', $data) ? (float) $data['pos_x'] : (float) $character->pos_x;
+        $z = array_key_exists('pos_z', $data) ? (float) $data['pos_z'] : (float) $character->pos_z;
+
+        $nearby = CityPlazas::nearestEquipment(
+            $character->city,
+            $x,
+            $z,
+            4.0,
+        );
+
+        if ($nearby === null) {
+            return response()->json(['message' => __('city.exercise_need_equipment')], 422);
+        }
+
+        if ((int) $character->energy < 5) {
+            return response()->json(['message' => __('city.exercise_tired')], 422);
+        }
+
+        if ((int) $character->health >= 100) {
+            return response()->json([
+                'message' => __('city.exercise_max_health'),
+                'character' => $this->characterData($character),
+            ]);
+        }
+
+        $character->forceFill([
+            'state' => Character::STATE_EXERCISING,
+            'health' => min(100, (int) $character->health + 2),
+            'energy' => max(0, (int) $character->energy - 2),
+            'exercise_count' => (int) $character->exercise_count + 1,
+            'pos_x' => $x,
+            'pos_z' => $z,
+        ])->save();
+
+        return response()->json([
+            'message' => __('city.exercise_ok'),
+            'equipment' => $nearby,
+            'character' => $this->characterData($character),
+        ]);
+    }
+
+    /**
+     * Leave the exercising state (back to awake).
+     */
+    private function stopExercise(Character $character): JsonResponse
+    {
+        if ($character->state === Character::STATE_EXERCISING) {
+            $character->state = Character::STATE_AWAKE;
+            $character->save();
+        }
+
+        return response()->json([
+            'message' => __('city.action_ok'),
+            'character' => $this->characterData($character),
+        ]);
+    }
+
     /**
      * Admit the character to the hospital after a vehicle collision.
      *
-     * Stays two game days (Character::HOSPITAL_STAY_SECONDS).
+     * Stays one game hour (Character::HOSPITAL_STAY_SECONDS).
      */
     private function accident(Character $character): JsonResponse
     {
@@ -483,7 +560,9 @@ class CityActionController extends Controller
             'energy' => (int) $character->energy,
             'hunger' => (int) $character->hunger,
             'thirst' => (int) $character->thirst,
+            'health' => (int) $character->health,
             'education' => (int) $character->education,
+            'exercise_count' => (int) $character->exercise_count,
             'job_id' => $character->job_id,
             'job_title' => $character->job?->title,
             'house_id' => $character->house_id,