feat:實作評價系統 — 匿名評價、有幫助投票、手動完成預約

後端：
- 新增 reviews / review_edits / review_votes migration（含索引）
- Review / ReviewEdit / ReviewVote Model
- ReviewController：評價 CRUD、資格驗證（completed booking）、rating 即時重算
- toggleHelpful：Member 限定、GREATEST 原子防負、DB transaction 同步
- AdminReviewController：全量列表、刪除（含重算）
- AdminBookingController：全量列表、手動標記 completed
- ProviderBookingController 新增 complete 方法（教練手動完成預約）
- DevelopmentSeeder：快速重建測試資料（admin/coach/member + offers + bookings）
- EnsureAdmin middleware 正式納入 bootstrap/app.php
- Nginx server_name 加入 cfdive.local

前端：
- 課程詳情頁加入評價區塊（星等分布、排序切換、撰寫/修改/刪除、有幫助 Toggle）
- Coach Portal 新增「課程評價」頁（只讀，依課程分組）
- Coach 預約管理加入「完成」按鈕
- Admin 新增「預約管理」頁（標記完成）、「評價管理」頁（刪除）
- Admin / Coach Navbar 新增對應連結

OpenSpec：
- review-system change 歸檔至 archive/2026-05-12-review-system
- 新增 specs/review-lifecycle 與 specs/review-voting 主規格
- review-voting spec 補充 Member 限定與 GREATEST 原子更新說明

Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

app/Http/Controllers/API/AdminReviewController.php

@@ -0,0 +1,56 @@
+<?php
+
+namespace App\Http\Controllers\API;
+
+use App\Http\Controllers\Controller;
+use App\Models\DivingOffer;
+use App\Models\Review;
+use Illuminate\Http\Request;
+use Illuminate\Support\Facades\DB;
+
+class AdminReviewController extends Controller
+{
+    public function index()
+    {
+        $reviews = Review::with(['divingOffer', 'member'])
+            ->orderByDesc('created_at')
+            ->get()
+            ->map(fn($r) => [
+                'id'          => $r->id,
+                'offer_title' => $r->divingOffer?->title,
+                'member_email'=> $r->member?->email,
+                'rating'      => $r->rating,
+                'comment'     => mb_strimwidth($r->comment, 0, 50, '...'),
+                'is_edited'   => $r->is_edited,
+                'helpful_count'=> $r->helpful_count,
+                'created_at'  => $r->created_at?->toISOString(),
+            ]);
+
+        return response()->json(['status' => true, 'data' => $reviews]);
+    }
+
+    public function destroy(int $id)
+    {
+        $review  = Review::findOrFail($id);
+        $offerId = $review->diving_offer_id;
+
+        DB::transaction(function () use ($review, $offerId) {
+            $review->delete();
+            $this->recalculateOfferRating($offerId);
+        });
+
+        return response()->json(['status' => true, 'message' => '評價已刪除']);
+    }
+
+    private function recalculateOfferRating(int $offerId): void
+    {
+        $stats = Review::where('diving_offer_id', $offerId)
+            ->selectRaw('ROUND(AVG(rating), 1) as avg_rating, COUNT(*) as total')
+            ->first();
+
+        DivingOffer::where('id', $offerId)->update([
+            'rating'  => $stats->total > 0 ? $stats->avg_rating : 0,
+            'reviews' => $stats->total,
+        ]);
+    }
+}