Add dry-run mode for XDC system workflows

[laniehei]

Summary

• Adds a worker.dryRunMode dynamic config flag that, when enabled on a cell, causes XDC system workflows (force-replication, namespace-handover) to complete immediately without doing real work
• This enables testing control plane globalization/failover/deglobalization code paths end-to-end without the time complexity of actually running force replication (which can take hours)

Motivation

The control plane CICD MultiRegionSuite tests invoke real temporal server system workflows (force-replication, handover) on test cells. Force replication lists, replicates, and verifies all workflows between cells, taking hours.

The tradeoff with alternative approaches (e.g., mocking the data-plane client interface in the control plane) is that mock interfaces don't stay up to date as the server evolves. With this approach, all control plane code paths execute against a real temporal server with real gRPC serialization — the server just returns immediately from XDC workflows when dry-run mode is enabled.

Changes

• common/dynamicconfig/constants.go: New WorkerDryRunMode global bool setting (default false)
• service/worker/migration/activities.go: dryRunMode field on activities struct + IsDryRunMode local activity
• service/worker/migration/fx.go: Wire WorkerDryRunMode into activities
• service/worker/migration/force_replication_workflow.go: isDryRunMode helper + skip checks in V1 and V2 (after query handler setup)
• service/worker/migration/handover_workflow.go: Skip check after param validation (V2 delegates to V1, so covered)

Enabling on a cell

# Via dynamic config
{"worker.dryRunMode": [{"value": true}]}

Test plan

• go test -tags test_dep ./service/worker/migration/... passes
• go build ./... compiles

🤖 Generated with Claude Code

[dnr]

make the name more accurate? there's other stuff going on in the worker besides xdc

Suggested change

	WorkerDryRunMode = NewGlobalBoolSetting(
	"worker.dryRunMode",
	WorkerXDCDryRunMode = NewGlobalBoolSetting(
	"worker.xdcDryRunMode",