feat(gateway): 未知模型缺价发结构化告警——成本账缺项可观测（CR-M2-1）

packages/llm_gateway/ww_llm_gateway/pricing.py

@@ -9,6 +9,10 @@ from __future__ import annotations
 import math
 from dataclasses import dataclass
 
+import structlog
+
+log = structlog.get_logger(__name__)
+
 
 @dataclass(frozen=True)
 class Price:
@@ -26,6 +30,9 @@ _PRICING: dict[tuple[str, str], Price] = {
 def cost_minor(provider: str, model: str, input_tokens: int, output_tokens: int) -> tuple[int, str]:
     price = _PRICING.get((provider, model))
     if price is None:
+        # 缺价条目应在成本账路径可见（CR-M2-1）：成本仍计 0（照常记账不阻断调用），
+        # 但发 warning 点名该 (provider, model)，否则漏配价格会静默吞成 0 成本。
+        log.warning("pricing_unknown_model", provider=provider, model=model)
         return 0, "USD"
     cost = math.ceil(
         input_tokens / 1_000_000 * price.in_per_mtok