feat(billing): 计费商业化重构(积分制)+ 团队差异化调价

统一计价引擎 apps/billing/pricing.py:1积分=¥0.1,平台成本(¥)与用户价(积分)双记账,
视频按火山真实 usage.total_tokens 结算(true-up,终结¥1/段倒贴)+ 首发×1.5毛利系数。
Team.price_multiplier 差异化调价(jimeng同款):挂牌价×系数两步HALF_UP取整,视频类
按下单时的价格/汇率快照结算(中途改配不影响在途任务)。

BillingConfig 单例(汇率/毛利系数/预留buffer,admin可调即刻生效)。存量数据 ×10 rescale
迁移(RunPython+atomic,MySQL 迁移不可中断重跑)。开户赠送归零(DEFAULT_TRIAL_CREDITS=0,
商业决策)。audit_billing 加 I9(卖亏审计)。271 条测试 + tsc/build 全绿。

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

core/backend/apps/accounts/tests.py

@@ -54,9 +54,15 @@ class AuthApiTests(TestCase):
         account = CreditAccount.objects.get(team=team)
         self.assertEqual(account.balance, trial)
         genesis = CreditLedger.objects.filter(team=team, ledger_type=CreditLedger.Type.RECHARGE)
-        self.assertEqual(genesis.count(), 1)
-        self.assertEqual(genesis.first().amount, trial)
-        self.assertEqual(genesis.first().balance_after, trial)  # 流水终点 == 账户余额,可对账
+        if trial > 0:
+            # 若运营期把赠送额度调回 >0,genesis 凭证契约必须成立(I8)
+            self.assertEqual(genesis.count(), 1)
+            self.assertEqual(genesis.first().amount, trial)
+            self.assertEqual(genesis.first().balance_after, trial)  # 流水终点 == 账户余额,可对账
+        else:
+            # 商业决策(2026-07-03):开户不赠送 → 余额 0 且不落赠送流水(I8 隐含余额 0 天然满足)
+            self.assertEqual(trial, Decimal("0"))
+            self.assertEqual(genesis.count(), 0)
 
 
 class InvitationFlowTests(TestCase):
@@ -150,7 +156,7 @@ class MemberQuotaAndRoleTests(TestCase):
         r = self._register(APIClient(), "solo-owner", team_name="Solo", invite_code=make_create_team_code())
         self.assertEqual(r.data.get("role"), "owner")
 
-    def test_create_member_defaults_limit_100(self):
+    def test_create_member_defaults_limit_1000(self):
         res = self.owner_client.post(
             "/api/auth/team/members/",
             {"username": "sub-a", "password": "strong-password", "role": "member"},
@@ -158,7 +164,8 @@ class MemberQuotaAndRoleTests(TestCase):
         )
         self.assertEqual(res.status_code, 201, res.content)
         member = TeamMember.objects.get(user__username="sub-a", team=self.team)
-        self.assertEqual(member.monthly_credit_limit, Decimal("100"))
+        # 积分制:默认月限额跟随 ×10(¥100 → 1000 积分),否则新成员限额实际缩水 10 倍
+        self.assertEqual(member.monthly_credit_limit, Decimal("1000"))
 
     def test_create_member_explicit_limit_respected(self):
         res = self.owner_client.post(