feat: feed selector health and demote in-call failed sources

RetryMW keeps a per-call failure map (local, never instance state):
a source failing twice in one call yields to the next candidate.
Attempt outcomes feed OutcomeAwareSelector behind a swallow-and-warn
guard; ResultInvalid and provider-rejected paths record success with
count_attempt=False so the breaker window stays clean. Same accounting
applied in EmbeddingClient.

src/polygateway/middleware/retry.py

@@ -32,6 +32,7 @@ from polygateway.errors import (
 )
 from polygateway.middleware.breaker import BreakerGate
 from polygateway.middleware.ratelimit import QuotaGate
+from polygateway.ports import OutcomeAwareSelector
 from polygateway.sources import SourceCooldownMemo
 from polygateway.streaming import StreamLivenessTimeout
 from polygateway.types import LLMResponse
@@ -72,6 +73,16 @@ def backoff_delay(
     return max(delay, retry_after)
 
 
+def _demote_call_failures(
+    ordered: list[SourceConfig], attempt_fails: dict[str, int]
+) -> list[SourceConfig]:
+    """调用内降权(设计 §3.3): 本调用失败 ≥2 次的源移尾;全失败则保持原序。"""
+    demoted = [s for s in ordered if attempt_fails.get(s.name, 0) >= 2]
+    if not demoted or len(demoted) == len(ordered):
+        return ordered
+    return [s for s in ordered if attempt_fails.get(s.name, 0) < 2] + demoted
+
+
 def _failure_reason(exc: PolyGatewayError) -> str:
     """失败原因归类(CHS governance.py:169 同款)。"""
     if isinstance(exc, SourceDeadError):
@@ -124,6 +135,8 @@ class RetryMW:
         self._bp = backpressure
         self._quota_full = quota_full
         self._memo = cooldown_memo or SourceCooldownMemo(now=now)
+        # M2.5: 选源器可选健康喂数端口,构造期 isinstance 判定一次(设计 §3.2)
+        self._outcome_sink = selector if isinstance(selector, OutcomeAwareSelector) else None
         self._emitter = emitter
         self._now = now
         self._sleep = sleep
@@ -135,13 +148,15 @@ class RetryMW:
             raise AllSourcesExhausted(scope=self._scope, reason="no_sources", retry_after_s=0.0)
         fails = 0
         reasons: dict[str, str] = {}
+        # 调用内失败计数(设计 §3.3): 局部状态,调用结束即弃;严禁实例属性(并发共享)
+        attempt_fails: dict[str, int] = {}
         entered_at = self._now()  # 调用级累计计时,循环内不重置(CHS governance.py:207)
         while True:
-            picked, gate_rejections = await self._pick_runnable(reasons)
+            picked, gate_rejections = await self._pick_runnable(reasons, attempt_fails)
             if picked is None:
                 await self._on_no_runnable(gate_rejections, reasons, entered_at)
                 continue
-            outcome = await self._attempt(request, *picked, reasons)
+            outcome = await self._attempt(request, *picked, reasons, attempt_fails)
             if isinstance(outcome, LLMResponse):
                 return outcome
             fails += 1
@@ -158,11 +173,12 @@ class RetryMW:
     # —— 选源与准入(CHS _pick_runnable 120-167)——
 
     async def _pick_runnable(
-        self, reasons: dict[str, str]
+        self, reasons: dict[str, str], attempt_fails: dict[str, int]
     ) -> tuple[tuple[SourceConfig, Permit, GateDecision] | None, int]:
         stats = {s.name: await self._quota.stats(s) for s in self._sources}
         gate_rejections = 0
-        for cand in self._selector.order(self._sources, stats):
+        ordered = _demote_call_failures(self._selector.order(self._sources, stats), attempt_fails)
+        for cand in ordered:
             if self._memo.active(cand.name):
                 # 冷却备忘跳过也计入拒绝数,保住 circuit_open 判据(CHS 同款)
                 gate_rejections += 1
@@ -228,6 +244,7 @@ class RetryMW:
         permit: Permit,
         entry: GateDecision,
         reasons: dict[str, str],
+        attempt_fails: dict[str, int],
     ) -> LLMResponse | _Failed:
         call_id = str(uuid.uuid4())
         started = self._now()
@@ -243,6 +260,7 @@ class RetryMW:
             actual = result.prompt_tokens + result.completion_tokens
             await self._record_quietly(self._breaker.record_success(entry))
             await self._record_quietly(self._quota.mark_progress())
+            self._feed_outcome(source.name, ok=True)
             response = self._build_response(source, result, call_id, started)
             await self._emit(request, source, call_id, started, response=response)
             return response
@@ -251,8 +269,8 @@ class RetryMW:
             await self._emit(request, source, call_id, started, error=exc)
             raise
         except ResultInvalidError as exc:
-            # 坏结果 ≠ 坏服务: 熔断记成功,异常上抛消耗业务失败预算(§6.3)
-            await self._record_quietly(self._breaker.record_success(entry))
+            # 坏结果 ≠ 坏服务: 熔断记成功但不计窗口样本,亦不喂健康分(M2.5 §3.1)
+            await self._record_quietly(self._breaker.record_success(entry, count_attempt=False))
             await self._emit(request, source, call_id, started, error=exc)
             raise
         except asyncio.CancelledError:
@@ -264,6 +282,8 @@ class RetryMW:
             dead = isinstance(exc, SourceDeadError)
             reason = _failure_reason(exc)
             reasons[source.name] = reason
+            attempt_fails[source.name] = attempt_fails.get(source.name, 0) + 1
+            self._feed_outcome(source.name, ok=False)
             await self._record_quietly(self._breaker.record_failure(entry, reason, dead))
             if not dead:
                 actual = source.est_tokens  # 保守: 失败请求可能已被网关计费(CHS 同款)
@@ -277,8 +297,8 @@ class RetryMW:
     ) -> None:
         provider_responded = exc.source_name == source.name and exc.status_code is not None
         if provider_responded:
-            # 网关健康地拒了坏请求
-            await self._record_quietly(self._breaker.record_success(entry))
+            # 网关健康地拒了坏请求: 记成功但不计窗口样本(M2.5 §3.1)
+            await self._record_quietly(self._breaker.record_success(entry, count_attempt=False))
         elif entry.is_probe:
             await self._record_quietly(self._breaker.release_probe(entry))
 
@@ -296,6 +316,15 @@ class RetryMW:
         except GovernanceBackendError as exc:
             logger.warning("治理记账写回降级(不冒泡): {}", exc)
 
+    def _feed_outcome(self, source_name: str, ok: bool) -> None:
+        """健康喂数降级执行: 选源器异常不得打断真实成功/失败的主路径(设计 §4)。"""
+        if self._outcome_sink is None:
+            return
+        try:
+            self._outcome_sink.record_outcome(source_name, ok)
+        except Exception as exc:
+            logger.warning("选源健康喂数失败(降级不冒泡): {}", exc)
+
     # —— 辅助 ——
 
     def _backoff_delay(self, fails: int, exc: PolyGatewayError) -> float: