feat(submitqueue): Add queuepause Store contract and QueuePause entity

Makefile

@@ -632,6 +632,7 @@ GO_GENERATE_PACKAGES := \
 	./submitqueue/extension/changeprovider/... \
 	./submitqueue/extension/conflict/... \
 	./submitqueue/extension/queueconfig/... \
+	./submitqueue/extension/queuepause/... \
 	./submitqueue/extension/speculation/... \
 	./submitqueue/extension/storage/... \
 	./submitqueue/extension/validator/... \

submitqueue/entity/BUILD.bazel

@@ -16,6 +16,7 @@ go_library(
         "path_build.go",
         "queue_batch_state.go",
         "queue_config.go",
+        "queue_pause.go",
         "request.go",
         "request_batch.go",
         "request_history.go",

submitqueue/entity/queue_pause.go

@@ -0,0 +1,29 @@
+// Copyright (c) 2026 Uber Technologies, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package entity
+
+// QueuePause is a point-in-time snapshot of the pause switches of a single
+// queue. The two switches are independent, and the zero value means the queue
+// is not paused.
+type QueuePause struct {
+	// RejectLands is true while the queue refuses new land requests.
+	RejectLands bool
+
+	// FreezeProcessing is true while the queue's accepted requests are not advanced.
+	FreezeProcessing bool
+
+	// Reason is the operator's free-text explanation for the pause. Empty when none was given.
+	Reason string
+}

submitqueue/extension/queuepause/BUILD.bazel

@@ -0,0 +1,9 @@
+load("@rules_go//go:def.bzl", "go_library")
+
+go_library(
+    name = "go_default_library",
+    srcs = ["queuepause.go"],
+    importpath = "github.com/uber/submitqueue/submitqueue/extension/queuepause",
+    visibility = ["//visibility:public"],
+    deps = ["//submitqueue/entity:go_default_library"],
+)

submitqueue/extension/queuepause/README.md

@@ -0,0 +1,15 @@
+# Queue Pause Extension
+
+Vendor-agnostic source of per-queue pause state. See [the pause and unpause RFC](../../../doc/rfc/submitqueue/queue-pause-and-unpause.md) for the design.
+
+## Interfaces
+
+### Store
+
+Returns the pause state of a queue by name. The state is two independent switches: reject new land requests, and freeze processing of accepted requests. A queue with no entry is not paused, and an error means the backend could not be read.
+
+The store only reports state. The gateway and orchestrator enforce it, so every deployment runs the same rejection and freezing logic and only the source of the state differs.
+
+## Entities
+
+`QueuePause` lives in `submitqueue/entity/queue_pause.go`.

submitqueue/extension/queuepause/mock/BUILD.bazel

@@ -0,0 +1,12 @@
+load("@rules_go//go:def.bzl", "go_library")
+
+go_library(
+    name = "go_default_library",
+    srcs = ["queuepause_mock.go"],
+    importpath = "github.com/uber/submitqueue/submitqueue/extension/queuepause/mock",
+    visibility = ["//visibility:public"],
+    deps = [
+        "//submitqueue/entity:go_default_library",
+        "@org_uber_go_mock//gomock:go_default_library",
+    ],
+)

submitqueue/extension/queuepause/queuepause.go

@@ -0,0 +1,34 @@
+// Copyright (c) 2026 Uber Technologies, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package queuepause
+
+//go:generate mockgen -source=queuepause.go -destination=mock/queuepause_mock.go -package=mock
+
+import (
+	"context"
+
+	"github.com/uber/submitqueue/submitqueue/entity"
+)
+
+// Store is the source of per-queue pause state. It reports the switches and
+// decides nothing; enforcement lives in the services that resolve it.
+type Store interface {
+	// Get returns the current pause state of a queue. A queue with no entry
+	// returns the zero state (not paused) and no error. A non-nil error means
+	// the backend could not be read, not that the queue is unpaused; a caller
+	// that enforces a switch must not fail open on it. Implementations must be
+	// safe for concurrent use.
+	Get(ctx context.Context, queue string) (entity.QueuePause, error)
+}