🏆 Add highscore feature with API endpoints, validations, and tests

- **Added:** Endpoints for submitting highscores (`highscores.store`) and retrieving the leaderboard (`highscores.index`).
- **Implemented:** Validation rules via `StoreHighscoreRequest` to ensure highscore integrity.
- **Included:** `Highscore` model, migration, and factory for data handling and seeding.
- **Enhanced:** Comprehensive feature tests covering submission, updating, retrieval, and payload validation.

app/Http/Controllers/Api/HighscoreController.php

@@ -0,0 +1,72 @@
+<?php
+
+namespace App\Http\Controllers\Api;
+
+use App\Http\Controllers\Controller;
+use App\Http\Requests\StoreHighscoreRequest;
+use App\Models\Highscore;
+use Carbon\CarbonImmutable;
+use Illuminate\Http\JsonResponse;
+use Illuminate\Support\Facades\Log;
+
+class HighscoreController extends Controller
+{
+    public function index(): JsonResponse
+    {
+        // npub1pt0kw36ue3w2g4haxq3wgm6a2fhtptmzsjlc2j2vphtcgle72qesgpjyc6
+        $highscores = Highscore::query()
+            ->orderByDesc('satoshis')
+            ->orderBy('achieved_at')
+            ->get()
+            ->map(fn (Highscore $highscore) => [
+                'npub' => $highscore->npub,
+                'name' => $highscore->name,
+                'satoshis' => $highscore->satoshis,
+                'blocks' => $highscore->blocks,
+                'datetime' => $highscore->achieved_at->toIso8601String(),
+            ]);
+
+        return response()->json([
+            'data' => $highscores,
+        ]);
+    }
+
+    public function store(StoreHighscoreRequest $request): JsonResponse
+    {
+        $validated = $request->validated();
+        $achievedAt = CarbonImmutable::parse($validated['datetime']);
+
+        $highscore = Highscore::query()->firstOrNew([
+            'npub' => $validated['npub'],
+            'achieved_at' => $achievedAt,
+        ]);
+
+        $highscore->satoshis = (int) $validated['satoshis'];
+        $highscore->blocks = (int) $validated['blocks'];
+
+        if (array_key_exists('name', $validated)) {
+            $highscore->name = $validated['name'];
+        }
+
+        $highscore->save();
+
+        Log::info('Highscore submission received', [
+            'npub' => $highscore->npub,
+            'name' => $highscore->name,
+            'satoshis' => $highscore->satoshis,
+            'blocks' => $highscore->blocks,
+            'datetime' => $highscore->achieved_at->toIso8601String(),
+        ]);
+
+        return response()->json([
+            'message' => 'Highscore received',
+            'data' => [
+                'npub' => $highscore->npub,
+                'name' => $highscore->name,
+                'satoshis' => $highscore->satoshis,
+                'blocks' => $highscore->blocks,
+                'datetime' => $highscore->achieved_at->toIso8601String(),
+            ],
+        ], 202);
+    }
+}