feat: [roadmap] 중장기 계획 메뉴 및 전용 페이지 개발

- 모델: AdminRoadmapPlan, AdminRoadmapMilestone
- 서비스: RoadmapPlanService, RoadmapMilestoneService
- FormRequest: Store/Update Plan/Milestone 4개
- 컨트롤러: Blade(RoadmapController), API(Plan/Milestone) 3개
- 라우트: web.php, api.php에 roadmap 라우트 추가
- Blade 뷰: 대시보드, 목록, 생성, 수정, 상세, 파셜 테이블 6개
- HTMX 기반 필터링/페이지네이션, 마일스톤 인라인 추가/토글

app/Http/Controllers/RoadmapController.php

@@ -0,0 +1,79 @@
+<?php
+
+namespace App\Http\Controllers;
+
+use App\Models\Admin\AdminRoadmapPlan;
+use App\Services\Roadmap\RoadmapPlanService;
+use Illuminate\View\View;
+
+class RoadmapController extends Controller
+{
+    public function __construct(
+        private readonly RoadmapPlanService $planService
+    ) {}
+
+    public function index(): View
+    {
+        $summary = $this->planService->getDashboardSummary();
+        $statuses = AdminRoadmapPlan::getStatuses();
+        $categories = AdminRoadmapPlan::getCategories();
+        $priorities = AdminRoadmapPlan::getPriorities();
+        $phases = AdminRoadmapPlan::getPhases();
+
+        return view('roadmap.index', compact(
+            'summary', 'statuses', 'categories', 'priorities', 'phases'
+        ));
+    }
+
+    public function plans(): View
+    {
+        $statuses = AdminRoadmapPlan::getStatuses();
+        $categories = AdminRoadmapPlan::getCategories();
+        $priorities = AdminRoadmapPlan::getPriorities();
+        $phases = AdminRoadmapPlan::getPhases();
+
+        return view('roadmap.plans.index', compact('statuses', 'categories', 'priorities', 'phases'));
+    }
+
+    public function createPlan(): View
+    {
+        $statuses = AdminRoadmapPlan::getStatuses();
+        $categories = AdminRoadmapPlan::getCategories();
+        $priorities = AdminRoadmapPlan::getPriorities();
+        $phases = AdminRoadmapPlan::getPhases();
+
+        return view('roadmap.plans.create', compact('statuses', 'categories', 'priorities', 'phases'));
+    }
+
+    public function showPlan(int $id): View
+    {
+        $plan = $this->planService->getPlanById($id, true);
+        if (! $plan) {
+            abort(404, '계획을 찾을 수 없습니다.');
+        }
+        $statuses = AdminRoadmapPlan::getStatuses();
+        $categories = AdminRoadmapPlan::getCategories();
+        $priorities = AdminRoadmapPlan::getPriorities();
+        $phases = AdminRoadmapPlan::getPhases();
+
+        return view('roadmap.plans.show', compact(
+            'plan', 'statuses', 'categories', 'priorities', 'phases'
+        ));
+    }
+
+    public function editPlan(int $id): View
+    {
+        $plan = $this->planService->getPlanById($id, true);
+        if (! $plan) {
+            abort(404, '계획을 찾을 수 없습니다.');
+        }
+        $statuses = AdminRoadmapPlan::getStatuses();
+        $categories = AdminRoadmapPlan::getCategories();
+        $priorities = AdminRoadmapPlan::getPriorities();
+        $phases = AdminRoadmapPlan::getPhases();
+
+        return view('roadmap.plans.edit', compact(
+            'plan', 'statuses', 'categories', 'priorities', 'phases'
+        ));
+    }
+}