feat: add GymController and gym routes

app/Http/Controllers/Game/GymController.php

@@ -0,0 +1,51 @@
+<?php
+
+namespace App\Http\Controllers\Game;
+
+use App\Http\Controllers\Controller;
+use App\Services\Game\TrainingService;
+use Illuminate\Http\RedirectResponse;
+use Illuminate\Http\Request;
+use Illuminate\View\View;
+
+class GymController extends Controller
+{
+    protected TrainingService $trainingService;
+
+    public function __construct()
+    {
+        $this->trainingService = new TrainingService();
+    }
+
+    public function index(Request $request): View
+    {
+        $character  = $request->user()->character;
+        $dailyCap   = config('game.gym.daily_cap', 5);
+        $energyCost = config('game.gym.energy_cost', 20);
+
+        $stats = [];
+        foreach (['strength', 'defense', 'speed', 'dexterity'] as $stat) {
+            $stats[$stat] = [
+                'value'             => $character->$stat,
+                'sessions_today'    => $this->trainingService->getSessionsToday($character, $stat),
+                'sessions_remaining'=> $this->trainingService->getSessionsRemaining($character, $stat),
+            ];
+        }
+
+        return view('game.gym.index', compact('character', 'stats', 'energyCost', 'dailyCap'));
+    }
+
+    public function train(Request $request): RedirectResponse
+    {
+        $request->validate(['stat' => 'required|in:strength,defense,speed,dexterity']);
+
+        $character = $request->user()->character;
+        $result    = $this->trainingService->train($character, $request->stat);
+
+        if ($result['success']) {
+            return redirect()->route('game.gym.index')->with('success', $result['message']);
+        }
+
+        return redirect()->route('game.gym.index')->with('error', $result['message']);
+    }
+}