feat(compute): 算力中心 余额门控+充值+真实来源数值

- relay 匿名不再回落admin令牌(root无限额)→401或受限RELAY令牌(修无余额可用)
- /admin/compute/user-balance(充值add/subtract/override)+审计; compute_client.adjust_user_quota
- proxy follow_redirects(修gin尾斜杠301/307空数据); ping 返 version+quota_per_unit

app/api/schemas/operator.py

@@ -1,4 +1,4 @@
-from pydantic import BaseModel
+from pydantic import BaseModel, Field
 
 class TaskCreateRequest(BaseModel):
     title: str
@@ -168,9 +168,19 @@ class TestStatusRequest(BaseModel):
 class ComputePingResponse(BaseModel):
     ok: bool
     version: str | None = None
+    quota_per_unit: float | None = None   # 引擎 1 元 = 多少配额（500000 = $1），来自 /api/status
     detail: str | None = None
 
 
+class ComputeBalanceRequest(BaseModel):
+    """充值/调整引擎用户余额。``value`` 为配额单位（见 quota_per_unit）。"""
+
+    engine_user_id: int
+    value: int = Field(ge=0, description="调整量（配额单位），add/subtract 用")
+    mode: str = "add"  # add | subtract | override
+    reason: str = ""
+
+
 class ComputeProvisionRequest(BaseModel):
     user_id: str