Add child workflow versioning overrides

[Quinn-With-Two-Ns]

What was changed

Add child workflow versioning overrides

Why?

Match Go SDK temporalio/sdk-go#2707

Checklist

1. Closes

2. How was this tested:

3. Any docs updates needed?

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Note

Medium Risk
Changes worker-deployment routing for child starts and introduces new failure semantics; behavior depends on server 1.32+ and is marked experimental, but existing callers are unaffected unless they opt in.

Overview
Adds experimental child workflow versioning overrides so a parent can route a child independently of its own deployment/versioning settings, aligning with the Go SDK.

ChildWorkflowOptions.Builder.setVersioningOverride accepts existing pinned and auto-upgrade overrides plus a new VersioningOverride.OneTimeVersioningOverride (initial target build until one workflow task completes, then behavior follows the completing worker). Overrides are serialized on the start-child command via ProtoConverters and SyncWorkflowContext.

When the server rejects an override, child start failure is surfaced as ChildWorkflowFailure with cause InvalidVersioningOverrideFailure (mapped from START_CHILD_WORKFLOW_EXECUTION_FAILED_CAUSE_INVALID_VERSIONING_OVERRIDE in ChildWorkflowStateMachine). Temporal Server ≥ 1.32.0 is required for overrides and one-time routing.

Integration tests in WorkerVersioningTest cover pinned, auto-upgrade, and one-time child override routing across multiple worker build IDs.

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