feat: 即時預約聊天室（realtime booking chat）

## 新增功能
- 會員與教練在 confirmed 預約期間可互傳文字與圖片訊息
- Presence Channel 顯示對方在線狀態（即時加入/離線）
- 已讀回執：對方讀取訊息後即時更新
- 預約完成（completed）後訊息封存唯讀
- 圖片上傳使用 intervention/image 處理（移除 EXIF、限制尺寸、強制重新編碼）

## 通知系統
- 收到新訊息時 Bell Icon 即時更新（NotificationCreated via private channel）
- 預約列表卡片顯示未讀角標（GET /api/bookings/messages/unread-counts 批次查詢）
- 瀏覽器分頁在背景時推送 Web Notification

## 基礎建設
- 引入 Laravel Reverb 作為自架 WebSocket 伺服器
- docker-compose 新增 reverb service（連接 proxy_net，供 NPM 代理）
- 前端安裝 laravel-echo + pusher-js，初始化 Echo plugin
- Dockerfile 補 GD JPEG/WebP/FreeType 支援

## 清理
- 移除 test_broadcast.php 與 resources/js/echo.js（Blade 殘留）
- 移除 /ping、/testpost 測試路由
- channels.php 改用 class-based 授權語法，移除 debug log
- BookingChat.vue otherType 提取為 computed 消除重複
- docker-entrypoint.sh 健康檢查改用 env var 取代硬編碼密碼

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

docker-compose.yml

@@ -48,6 +48,8 @@ services:
     image: nginx:alpine
     container_name: cfdive-nginx
     restart: unless-stopped
+    ports:
+      - "127.0.0.1:8080:80"
     volumes:
       - ./:/var/www
       - ./docker/nginx/conf.d/:/etc/nginx/conf.d/
@@ -69,9 +71,15 @@ services:
       dockerfile: Dockerfile
       args:
         VITE_API_URL: ${VITE_API_URL:-https://api.hank-spack.com}
+        VITE_REVERB_APP_KEY: ${VITE_REVERB_APP_KEY}
+        VITE_REVERB_HOST: ${VITE_REVERB_HOST:-localhost}
+        VITE_REVERB_PORT: ${VITE_REVERB_PORT:-8085}
+        VITE_REVERB_SCHEME: ${VITE_REVERB_SCHEME:-http}
     image: cfdive-frontend
     container_name: cfdive-frontend
     restart: unless-stopped
+    ports:
+      - "127.0.0.1:5173:80"
     networks:
       - cfdive-network
       - proxy_net
@@ -156,6 +164,37 @@ services:
       timeout: 10s
       retries: 3
 
+  reverb:
+    image: cfdive-platform
+    container_name: cfdive-reverb
+    restart: unless-stopped
+    working_dir: /var/www/
+    entrypoint: ["php", "artisan", "reverb:start", "--host=0.0.0.0", "--port=8080"]
+    ports:
+      - "127.0.0.1:8085:8080"
+    volumes:
+      - ./:/var/www
+    environment:
+      - APP_KEY=${APP_KEY}
+      - REVERB_APP_ID=${REVERB_APP_ID}
+      - REVERB_APP_KEY=${REVERB_APP_KEY}
+      - REVERB_APP_SECRET=${REVERB_APP_SECRET}
+      - REVERB_HOST=reverb
+      - REVERB_PORT=8080
+      - REDIS_HOST=redis
+      - DB_CONNECTION=mysql
+      - DB_HOST=db
+      - DB_PORT=3306
+      - DB_DATABASE=${DB_DATABASE:-CFDivePlatform}
+      - DB_USERNAME=${DB_USERNAME:-cfdiveuser}
+      - DB_PASSWORD=${DB_PASSWORD}
+    networks:
+      - cfdive-network
+      - proxy_net
+    depends_on:
+      app:
+        condition: service_healthy
+
 networks:
   cfdive-network:
     driver: bridge