feat: 实现 iOS Apple Pay 内购支付功能

前端:
- 集成 in_app_purchase 插件，实现 IAP 支付流程
- 添加支付模块 (payments/) 处理产品获取、购买、验证
- 积分中心页面集成 Apple Pay 购买入口
- 设置页面重构: 关于/隐私/协议直接展示，删除 legal_center 子页面
- 修复欢迎引导页滚动检测阈值问题
- 修复解卦结果页 iOS 侧滑返回手势被阻止的问题
- 邀请码绑定按钮临时禁用（待后端实现）

后端:
- 新增 apple_iap_transactions 表记录交易
- 实现 Apple 服务器端验证 (App Store Server API)
- 支付成功后自动发放积分
- 支持 Sandbox/Production 环境切换
- 添加退款处理和交易状态机

协议:
- 更新积分流水协议，支持 purchase/refund 类型
- 新增 PAYMENT_* 错误码

docs/protocols/common/user-points-chat-data-protocol.md

@@ -34,6 +34,25 @@ Protocol verification status:
 - Billing idempotency key for per-run consume: `chat.run.success:{sha1(session_id:run_id)}`.
 - Failed/canceled runs do not deduct user points. If real provider cost is observed, audit record is written with `billed_to='platform'`.
 
+## Points Change Types (change_type)
+
+| Type | Direction | Meaning | biz_type | Description |
+|------|-----------|---------|----------|-------------|
+| `register` | +1 | 注册奖励 | `null` | 新用户注册赠送积分 |
+| `consume` | -1 | 消费扣减 | `chat` | 用户占卜消耗积分 |
+| `adjust` | ±1 | 手动调整 | `null` | 系统或管理员手动调整积分，通用调整不绑定业务场景 |
+| `purchase` | +1 | 购买入账 | `payment` | 用户支付购买积分 |
+| `refund` | -1 | 退款扣回 | `payment` | 退款后扣回积分 |
+
+## Points Business Types (biz_type)
+
+| Type | Meaning | Associated change_type |
+|------|---------|------------------------|
+| `chat` | 聊天/占卜业务 | `consume` |
+| `payment` | 支付业务 | `purchase`, `refund` |
+
+Note: `register` and `adjust` do not bind to any `biz_type` (they are `null`).
+
 ## Table contract
 
 ### profiles
@@ -62,21 +81,23 @@ Protocol verification status:
 - PK: `id`
 - FK:
   - `user_id -> auth.users.id` (`on delete cascade`)
-  - `biz_id -> sessions.id` (`on delete restrict`, nullable)
+  - `biz_id -> sessions.id` (`on delete restrict`, nullable) — only for `biz_type='chat'`
   - `operator_id -> auth.users.id` (`on delete set null`)
 - Core fields: `direction`, `amount`, `balance_after`, `change_type`, `biz_type`, `biz_id`, `event_id`, `operator_id`, `metadata`, `created_at`, `updated_at`
 - Constraints:
   - `amount > 0`
   - `direction in (1, -1)`
   - `balance_after >= 0`
-  - `change_type in ('register', 'consume', 'grant', 'adjust')`
-  - `biz_type is null or biz_type='chat'`
+  - `change_type in ('register', 'consume', 'adjust', 'purchase', 'refund')`
+  - `biz_type is null or biz_type in ('chat', 'payment')`
   - biz binding:
     - `register => biz_type is null and biz_id is null`
-    - `consume/grant/adjust => biz_type='chat' and biz_id not null`
+    - `consume => biz_type='chat' and biz_id not null`
+    - `adjust => biz_type is null and biz_id is null` (通用调整，不绑定业务场景)
+    - `purchase/refund => biz_type='payment' and biz_id not null` (biz_id references `apple_iap_transactions.id` as logical FK, not database FK)
   - direction and change_type coupling:
-    - `register/grant => direction = 1`
-    - `consume => direction = -1`
+    - `register/purchase => direction = 1`
+    - `consume/refund => direction = -1`
     - `adjust => direction in (1, -1)`
   - idempotency: `unique (user_id, event_id)`
 
@@ -89,8 +110,8 @@ Protocol verification status:
   - `amount >= 0`
   - `direction in (1, 0, -1)`
   - `balance_after >= 0`
-  - `change_type in ('register', 'consume', 'grant', 'adjust')`
-  - `biz_type is null or biz_type='chat'`
+  - `change_type in ('register', 'consume', 'adjust', 'purchase', 'refund')`
+  - `biz_type is null or biz_type in ('chat', 'payment')`
   - `billed_to in ('user', 'platform')`
   - metadata must be object
   - idempotency: `unique (event_id)`
@@ -141,8 +162,9 @@ JSON constraints:
 - Per `change_type`:
   - `register`: no `charge`, and no chat binding (`biz_type/biz_id` both null)
   - `consume`: requires `charge` object with required fields
-  - `grant`: no extra metadata shape requirement
-  - `adjust`: requires `ext.ticket_id` non-empty
+  - `adjust`: requires `ext.reason` non-empty (通用调整，系统或管理员均可操作，不绑定业务)
+  - `purchase`: requires `ext.source`, `ext.platform`, `ext.product_code`, `ext.transaction_id`
+  - `refund`: requires `ext.source`, `ext.platform`, `ext.product_code`, `ext.transaction_id`, `ext.original_event_id`
 
 ## Signup initialization contract
 
@@ -225,9 +247,9 @@ Returns available purchase packages for the current user's region, including sta
   "currency": "USD",
   "packages": [
     {
-      "productCode": "new_user_pack_099_60",
+      "productCode": "new_user_pack",
       "type": "starter",
-      "priceUsd": "0.99",
+      "price": "0.99",
       "credits": 60,
       "badge": null,
       "isStarter": true,
@@ -235,9 +257,9 @@ Returns available purchase packages for the current user's region, including sta
       "sortOrder": 0
     },
     {
-      "productCode": "basic_pack_499_100",
+      "productCode": "basic_pack",
       "type": "regular",
-      "priceUsd": "4.99",
+      "price": "4.99",
       "credits": 100,
       "badge": null,
       "isStarter": false,
@@ -252,9 +274,9 @@ Returns available purchase packages for the current user's region, including sta
 - `region`: ISO 3166-1 alpha-2 country code (e.g., "US", "CN")
 - `currency`: ISO 4217 currency code (e.g., "USD")
 - `packages`: List of available packages
-  - `productCode`: Unique product identifier
+  - `productCode`: Unique product identifier (e.g., `new_user_pack`, `basic_pack`, `popular_pack`, `premium_pack`)
   - `type`: "starter" (new user pack) or "regular"
-  - `priceUsd`: Price in USD (decimal string)
+  - `price`: Price in the response currency (decimal string, for display reference only; actual payment uses StoreKit price)
   - `credits`: Number of credits
   - `badge`: Optional badge text (e.g., "Popular")
   - `isStarter`: Whether this is a starter pack
@@ -277,16 +299,16 @@ Returns available purchase packages for the current user's region, including sta
 region: US
 currency: USD
 packages:
-  - product_code: new_user_pack_099_60
+  - product_code: new_user_pack
     type: starter
-    price_usd: "0.99"
+    price: "0.99"
     credits: 60
     badge: null
     sort_order: 0
     enabled: true
-  - product_code: basic_pack_499_100
+  - product_code: basic_pack
     type: regular
-    price_usd: "4.99"
+    price: "4.99"
     credits: 100
     badge: null
     sort_order: 10