Single workflow pause API (#8605)

## What changed?
Note: This API is part of an experimental feature - "pause single
workflow"

- Added a new API (in Frontend & History) to pause workflow execution.
- Updated DescribeWorkflowExecution API to show the pause info.
- Added a dynamic config to control the access to this feature. The
PauseWorkflowExecution API fails if the config is not set.
- Added simple acceptance functional tests. These tests will evolve and
new ones added as the feature implementation progresses.

Followup PRs:
- Idempotency check in pause api.
- Validate input sizes.
- Intercept workflow task creation.
- Intercept and pause activities.
- Unpause API


## Why?
This API is needed to implement the "pause single workflow" feature.

## How did you test it?
- [x] built
- [x] run locally and tested manually
- [ ] covered by existing tests
- [ ] added new unit test(s)
- [x] added new functional test(s)



<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> Adds a PauseWorkflowExecution API across frontend/history, wires
clients/GRPC/mocks, surfaces pause info in DescribeWorkflowExecution,
gates via new WorkflowPauseEnabled config, and adds functional tests.
> 
> - **APIs/Protos**:
> - Add `PauseWorkflowExecutionRequest/Response` messages in
`api/historyservice/v1/request_response.proto` and generated Go files.
> - Extend `HistoryService` with `PauseWorkflowExecution` RPC (server,
client, grpc, mocks).
> - **Frontend**:
> - Implement `WorkflowHandler.PauseWorkflowExecution`, resolving
namespace, invoking history, and gating by `WorkflowPauseEnabled`.
>   - Wire new config in `service.go`.
> - **History**:
> - Implement handler `PauseWorkflowExecution` in engine and new API
`service/history/api/pauseworkflow` to add paused event and handle
running-state checks.
> - Enhance `DescribeWorkflowExecution` to include `PauseInfo` in
`WorkflowExtendedInfo`.
> - **Clients**:
> - Add client methods (`client_gen`, `metric_client_gen`,
`retryable_client_gen`) and historyservice mocks.
> - **Config**:
> - Introduce `dynamicconfig.WorkflowPauseEnabled` (namespace-scoped)
and thread through frontend config.
> - **Telemetry/Logging**:
> - Add log tags for `PauseWorkflowExecution` and include RPC in
telemetry interceptor.
> - **Tests**:
> - Add functional tests `tests/pause_workflow_execution_test.go`
covering enabled/disabled scenarios.
> - **Dependencies**:
>   - Bump `go.temporal.io/api` version.
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
23e9f46. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

Author: gow

api/historyservice/v1/request_response.go-helpers.pb.go

@@ -1378,8 +1378,8 @@ second per poller by one physical queue manager`,
 	MatchingEnableWorkerPluginMetrics = NewGlobalBoolSetting(
 		"matching.enableWorkerPluginMetrics",
 		false,
-		`MatchingEnableWorkerPluginMetrics controls whether to export worker plugin metrics. 
-The metric has 2 dimensions: namespace_id and plugin_name. Disabled by default as this is 
+		`MatchingEnableWorkerPluginMetrics controls whether to export worker plugin metrics.
+The metric has 2 dimensions: namespace_id and plugin_name. Disabled by default as this is
 an optional feature and also requires a metrics collection system that can handle higher cardinalities.`,
 	)
 
@@ -1657,13 +1657,13 @@ NOTE: The outbound queue has a separate configuration: outboundQueueMaxPredicate
 	QueueMoveGroupTaskCountBase = NewGlobalIntSetting(
 		"history.queueMoveGroupTaskCountBase",
 		500,
-		`The base number of pending tasks count for a task group to be moved to the next level reader. 
+		`The base number of pending tasks count for a task group to be moved to the next level reader.
 The actual count is calculated as base * (multiplier ^ level)`,
 	)
 	QueueMoveGroupTaskCountMultiplier = NewGlobalFloatSetting(
 		"history.queueMoveGroupTaskCountMultiplier",
 		3.0,
-		`The multiplier used to calculate the number of pending tasks for a task group to be moved to the next level reader. 
+		`The multiplier used to calculate the number of pending tasks for a task group to be moved to the next level reader.
 The actual count is calculated as base * (multiplier ^ level)`,
 	)
 
@@ -2943,4 +2943,10 @@ WorkerActivitiesPerSecond, MaxConcurrentActivityTaskPollers.
 		false,
 		`WorkerCommandsEnabled is a "feature enable" flag. It allows clients to send commands to the workers.`,
 	)
+
+	WorkflowPauseEnabled = NewNamespaceBoolSetting(
+		"frontend.WorkflowPauseEnabled",
+		false,
+		`WorkflowPauseEnabled is a "feature enable" flag. When enabled it allows clients to pause workflows.`,
+	)
 )