feat(acceptance): 增加生产同构媒体压力验收模式

引入动态流量门禁、隔离验收身份与协议级 Gemini/Volces 模拟器，覆盖双站点 API、Worker、PostgreSQL、River、账务、回调和媒体物化链路。

新增 P24/P28/P32 容量阶梯、Worker 强杀恢复、真实小流量 canary、CAS 放量和失败保持 validation 的生产编排；Worker 执行槽、连接池、媒体并发和双站点副本数改为环境配置。

验证：Go 全量测试、真实 PostgreSQL 迁移集成测试、迁移安全检查、OpenAPI 生成、ShellCheck、Kustomize、gofmt 和 git diff --check。

Dockerfile

@@ -33,7 +33,9 @@ RUN --mount=type=cache,target=/go/pkg/mod \
     cd apps/api && \
     CGO_ENABLED=0 GOOS=$TARGETOS GOARCH=$TARGETARCH go build -trimpath -ldflags="-s -w" -o /out/easyai-ai-gateway ./cmd/gateway && \
     CGO_ENABLED=0 GOOS=$TARGETOS GOARCH=$TARGETARCH go build -trimpath -ldflags="-s -w" -o /out/easyai-ai-gateway-migrate ./cmd/migrate && \
-    CGO_ENABLED=0 GOOS=$TARGETOS GOARCH=$TARGETARCH go build -trimpath -ldflags="-s -w" -o /out/easyai-ai-gateway-backfill-binary-results ./cmd/backfill-binary-results
+    CGO_ENABLED=0 GOOS=$TARGETOS GOARCH=$TARGETARCH go build -trimpath -ldflags="-s -w" -o /out/easyai-ai-gateway-backfill-binary-results ./cmd/backfill-binary-results && \
+    CGO_ENABLED=0 GOOS=$TARGETOS GOARCH=$TARGETARCH go build -trimpath -ldflags="-s -w" -o /out/easyai-ai-gateway-acceptance-emulator ./cmd/acceptance-emulator && \
+    CGO_ENABLED=0 GOOS=$TARGETOS GOARCH=$TARGETARCH go build -trimpath -ldflags="-s -w" -o /out/easyai-ai-gateway-acceptance-load ./cmd/acceptance-load
 
 FROM ${API_RUNTIME_IMAGE} AS api
 
@@ -44,6 +46,8 @@ WORKDIR /app
 COPY --from=api-builder /out/easyai-ai-gateway /app/easyai-ai-gateway
 COPY --from=api-builder /out/easyai-ai-gateway-migrate /app/easyai-ai-gateway-migrate
 COPY --from=api-builder /out/easyai-ai-gateway-backfill-binary-results /app/easyai-ai-gateway-backfill-binary-results
+COPY --from=api-builder /out/easyai-ai-gateway-acceptance-emulator /app/easyai-ai-gateway-acceptance-emulator
+COPY --from=api-builder /out/easyai-ai-gateway-acceptance-load /app/easyai-ai-gateway-acceptance-load
 COPY apps/api/migrations /app/migrations
 
 RUN mkdir -p /app/data/static/generated /app/data/static/uploaded && \