feat(affiliate): 完善邀请返利系统

- 修复返利不到账的根因：tryClaimAffiliateRebateAudit 中 PostgreSQL 参数类型推断冲突
  - 补全 OAuth 注册路径（LinuxDo/OIDC/WeChat/Pending Flow）的邀请码绑定
  - 前端 OAuth 注册页面传递 aff_code 参数
  - 新增返利冻结期机制：可配置冻结时间，到期后自动解冻（懒解冻）
  - 新增返利有效期：绑定后 N 天内有效，过期不再产生返利
  - 新增单人返利上限：超出上限部分精确截断
  - 增强返利流程 slog 结构化日志，便于排查问题
  - 已邀请用户列表增加返利明细列

frontend/src/api/__tests__/auth-oauth-adoption.spec.ts

@@ -74,6 +74,26 @@ describe('oauth adoption auth api', () => {
     })
   })
 
+  it('posts affiliate code when completing linuxdo oauth registration', async () => {
+    const { completeLinuxDoOAuthRegistration } = await import('@/api/auth')
+
+    await completeLinuxDoOAuthRegistration(
+      'invite-code',
+      {
+        adoptDisplayName: true,
+        adoptAvatar: false
+      },
+      ' AFF123 '
+    )
+
+    expect(post).toHaveBeenCalledWith('/auth/oauth/linuxdo/complete-registration', {
+      invitation_code: 'invite-code',
+      aff_code: 'AFF123',
+      adopt_display_name: true,
+      adopt_avatar: false
+    })
+  })
+
   it('posts oidc invitation completion with adoption decisions', async () => {
     const { completeOIDCOAuthRegistration } = await import('@/api/auth')
 
@@ -134,6 +154,26 @@ describe('oauth adoption auth api', () => {
     })
   })
 
+  it('posts affiliate code when creating pending wechat oauth account', async () => {
+    const { createPendingWeChatOAuthAccount } = await import('@/api/auth')
+
+    await createPendingWeChatOAuthAccount(
+      'invite-code',
+      {
+        adoptDisplayName: false,
+        adoptAvatar: true
+      },
+      'WXAFF'
+    )
+
+    expect(post).toHaveBeenCalledWith('/auth/oauth/wechat/complete-registration', {
+      invitation_code: 'invite-code',
+      aff_code: 'WXAFF',
+      adopt_display_name: false,
+      adopt_avatar: true
+    })
+  })
+
   it('classifies oauth completion results as login or bind', async () => {
     const { getOAuthCompletionKind } = await import('@/api/auth')