docs: design the circuit-open wait policy for issue 14

The breaker conflates "this source is unhealthy" with "kill this call
now". Limiter rejections already choose between wait and fail_fast;
breaker rejections had no such choice, so a single-source scope loses
its whole retry budget the moment the gate opens.

Design adds {SCOPE}__CIRCUIT_OPEN (default fail_fast, so existing
deployments keep their control flow) and pins retry_after_s to "time
until a *certain* retry moment" across all six gate exits. The latter
also fixes a separate bug the issue missed: a half-open rejection fed
the probe lease (up to 2x timeout) into the source cooldown memo, whose
set_until only moves forward -- so a recovered source stayed blacklisted
in-process long after the gate closed. That one bites multi-source
deployments too, it is just hidden when other sources absorb the load.

Human-approved 2026-08-19; both documents revised after Codex review.

research-wiki/index.md

@@ -1,8 +1,8 @@
 # Research Wiki 索引
 
-> 自动生成，更新时间：2026-08-19 13:10 UTC
+> 自动生成，更新时间：2026-08-20 03:30 UTC
 
-## design (34)
+## design (35)
 - [2026-07-20-m1-core-design](designs/2026-07-20-m1-core-design.md) `design:2026-07-20-m1-core-design`
 - [2026-07-20-m2-distributed-design](designs/2026-07-20-m2-distributed-design.md) `design:2026-07-20-m2-distributed-design`
 - [2026-07-21-m25-resilience-design](designs/2026-07-21-m25-resilience-design.md) `design:2026-07-21-m25-resilience-design`
@@ -19,6 +19,7 @@
 - [2026-08-17-issue11-caller-dimensions-design](designs/2026-08-17-issue11-caller-dimensions-design.md) `design:2026-08-17-issue11-caller-dimensions-design`
 - [2026-08-19-issue12-telemetry-retention-design](designs/2026-08-19-issue12-telemetry-retention-design.md) `design:2026-08-19-issue12-telemetry-retention-design`
 - [2026-08-19-issue13-schema-mode-design](designs/2026-08-19-issue13-schema-mode-design.md) `design:2026-08-19-issue13-schema-mode-design`
+- [2026-08-19-issue14-admission-wait-policy-design](designs/2026-08-19-issue14-admission-wait-policy-design.md) `design:2026-08-19-issue14-admission-wait-policy-design`
 - [est_tokens 解耦: 拆分限流预扣与遥测用量兜底(issue #2)](designs/est-tokens-decoupling.md) `design:est-tokens-decoupling`
 - [GatewaySettings 装配校验补齐(第二轮)](designs/settings-invariants-round-2.md) `design:settings-invariants-round-2`
 - [GatewaySettings 跨字段不变量守卫的生效范围](designs/settings-invariant-guards.md) `design:settings-invariant-guards`
@@ -52,7 +53,7 @@
 - [P7 OCR soak 验收: 99.73% 与 13 不变量全 PASS](findings/p7-ocr-soak.md) `finding:p7-ocr-soak`
 - [推理开关与 reasoning_tokens: 供应商实测与业界做法](findings/2026-08-02-thinking-switch-and-reasoning-tokens.md) `finding:2026-08-02-thinking-switch-and-reasoning-tokens`
 
-## plan (29)
+## plan (30)
 - [2026-07-20-m1-core-plan](plans/2026-07-20-m1-core-plan.md) `plan:2026-07-20-m1-core-plan`
 - [2026-07-20-m2-distributed-plan](plans/2026-07-20-m2-distributed-plan.md) `plan:2026-07-20-m2-distributed-plan`
 - [2026-07-21-m25-resilience-plan](plans/2026-07-21-m25-resilience-plan.md) `plan:2026-07-21-m25-resilience-plan`
@@ -74,6 +75,7 @@
 - [M2.5 治理韧性实现计划](plans/m25-resilience.md) `plan:m25-resilience`
 - [M3 OCR 实现计划](plans/m3-ocr.md) `plan:m3-ocr`
 - [M4 迁移实现计划(T0-T14)](plans/m4-migration.md) `plan:m4-migration`
+- [plan-issue14-admission-wait-policy](plans/plan-issue14-admission-wait-policy.md) `plan:plan-issue14-admission-wait-policy`
 - [响应可观测字段扩展实现计划](plans/response-observability-fields.md) `plan:response-observability-fields`
 - [实现计划: HTTP 错误响应体留存(Issue #10)](plans/issue10-error-body-retention-plan.md) `plan:issue10-error-body-retention-plan`
 - [实现计划: issue12-telemetry-retention](plans/plan-issue12-telemetry-retention.md) `plan:plan-issue12-telemetry-retention`