Standalone Activity client and UI (#986)

## What was changed
Add Standalone Activity client support that was present in
[`v1.6.2-standalone-activity`](https://github.com/temporalio/cli/releases/tag/v1.6.2-standalone-activity).
This branch is that, rebased on `main`.

## How this was tested
The PR adds a test suite for Standalone Activity.

---------

Co-authored-by: Roey Berman <roey.berman@gmail.com>
Co-authored-by: Alex Stanfield <13949480+chaptersix@users.noreply.github.com>

Author: 3 people

internal/devserver/server.go

@@ -39,6 +39,7 @@ import (
 	uiconfig "github.com/temporalio/ui-server/v2/server/config"
 	uiserveroptions "github.com/temporalio/ui-server/v2/server/server_options"
 	"go.temporal.io/api/enums/v1"
+	"go.temporal.io/server/chasm/lib/activity"
 	"go.temporal.io/server/common/authorization"
 	"go.temporal.io/server/common/cluster"
 	"go.temporal.io/server/common/config"
@@ -240,6 +241,11 @@ func (s *StartOptions) buildServerOptions() ([]temporal.ServerOption, *slog.Leve
 	// Up default visibility RPS
 	dynConf[dynamicconfig.FrontendMaxNamespaceVisibilityRPSPerInstance.Key()] = 100
 
+	// Enable CHASM and SAA. These will be on by default in server v1.32, at which point these lines
+	// should be removed.
+	dynConf[dynamicconfig.EnableChasm.Key()] = true
+	dynConf[activity.Enabled.Key()] = true
+
 	// Dynamic config if set
 	for k, v := range s.DynamicConfigValues {
 		dynConf[dynamicconfig.MakeKey(k)] = v