fix: reject conflicting raw reasoning overrides before sending

src/polygateway/transports/openai_compat.py

@@ -34,6 +34,7 @@ from polygateway.thinking import (
     observe_thinking,
     reconcile_thinking,
     resolve_thinking,
+    validate_thinking_raw,
 )
 from polygateway.transports._http_errors import compose_message, summarize_body
 from polygateway.types import (
@@ -371,20 +372,23 @@ class OpenAICompatTransport:
         self._warned_models.add(source.model)
         # 三层优先级在此汇合: 请求级 > 源级 > enable_thinking 语法糖(设计 §4.2)。
         # 判定与装配守卫共用同一个纯函数,两处分叉就会变成"装配期放行、运行期报错"
+        effort = effective_effort(
+            request_effort=reasoning_effort,
+            source_effort=source.reasoning_effort,
+            enable_thinking=source.enable_thinking,
+        )
         resolution = resolve_thinking(
             profile,
             capability,
-            effective_effort(
-                request_effort=reasoning_effort,
-                source_effort=source.reasoning_effort,
-                enable_thinking=source.enable_thinking,
-            ),
+            effort,
             model=source.model,
             # 源级 `EFFORT_FALLBACK` 必须真的走到这里: 硬编码 "error" 会让人类明确
             # 要求实现的 `nearest` 在零告警下变成死代码(2026-09-05 独立验证查出)
             fallback=source.effort_fallback,
             warn_unregistered=first_time,
         )
+        for raw, origin in ((source.extra_body, "source extra_body"), (overlay, "request overlay")):
+            validate_thinking_raw(raw, effort=effort, wire=profile.thinking, origin=origin)
         payload.update(resolution.payload)
         # 顺序即优先级(issue #4 设计决策 A): 配置级 extra_body 在前,调用级
         # overlay(含结构化注入)在后覆盖之。两行不可调换