feat(core): notification inbox infinite scroll + command palette fix (+ pending WIP)

消息中心:全量渲染 → 真·后端分页滚动加载
- backend(ops/views): NotificationPagination(10/页,page_size 可覆盖)+
  响应回 type_counts(按收件人绝对计数,不受分页/搜索影响)
- frontend(messages): 自管分页,滚到底加载下一批;tab/搜索走服务端并重置到第1页;
  代号作废在途旧请求防切换卡空白;乐观标已读;「已加载 X / Y」分母用当前筛选总数
- api/App/types: listNotifications 支持 page/page_size/search;allNotifications 携带 type_counts

命令面板(侧边栏搜索):修复点开后 UI 错位
- app-shell: 遮罩 className 漏了基类 shell-command-bg(只有 .show)致无定位塌到左下;
  补回基类 + header 类名对齐 .shell-command-h
- messages-page.css: 工作台收进视口高度,收件箱在面板内滚动

本次提交一并带入此前若干未提交 WIP(account/ai-tools/library/pipeline/products/settings +
accounts/ai/assets/billing/projects 后端),按用户要求整体推 dev。

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

core/backend/apps/billing/services/ledger.py

@@ -29,7 +29,7 @@ def reserve_credit(*, team, user, task, amount: Decimal) -> CreditReservation:
         ledger_type=CreditLedger.Type.RESERVE,
         amount=amount,
         balance_after=account.balance,
-        reason="reserve ai task credit",
+        reason="AI 任务预扣额度",
     )
     return reservation
 
@@ -52,7 +52,7 @@ def release_credit(*, reservation: CreditReservation, reason: str = "") -> None:
         ledger_type=CreditLedger.Type.RELEASE,
         amount=reservation.amount,
         balance_after=account.balance,
-        reason=reason or "release reserved credit",
+        reason=reason or "释放预留额度",
     )
 
 
@@ -77,7 +77,7 @@ def charge_reserved_credit(*, reservation: CreditReservation, actual_amount: Dec
         ledger_type=CreditLedger.Type.CHARGE,
         amount=actual_amount,
         balance_after=account.balance,
-        reason="charge ai task credit",
+        reason="AI 任务扣费",
     )
     if reservation.amount > actual_amount:
         CreditLedger.objects.create(
@@ -88,6 +88,6 @@ def charge_reserved_credit(*, reservation: CreditReservation, actual_amount: Dec
             ledger_type=CreditLedger.Type.RELEASE,
             amount=reservation.amount - actual_amount,
             balance_after=account.balance,
-            reason="release unused reserved credit",
+            reason="释放未用预留额度",
         )