feat(workflows): Add workflow versioning patch support

[WhitWaldo]

Summary

Implement patch-based workflow versioning in the Dapr JS SDK, allowing developers to make backward-compatible changes to running workflow definitions without breaking in-flight instances.

Background

When a workflow definition is modified after instances are already running, replaying the history of those instances against the new code can produce non-determinism errors. Patch-based versioning solves this by allowing developers to branch logic based on whether an instance was started before or after a change.

This is sometimes called "version gates" — a mechanism to say "if this instance has already passed this point in execution, use the old logic; otherwise, use the new logic."

Proposed API

// In WorkflowContext:

/**
 * Returns true if the current instance should execute the new code path
 * identified by `patchName`. Returns false for instances that were started
 * before this patch was introduced (to preserve replay compatibility).
 */
isPatched(patchName: string): boolean;

Usage Example

function* myWorkflow(ctx: WorkflowContext, input: OrderInput) {
  // Original logic:
  const result = yield ctx.callActivity(processOrder, input);

  // Added later — new validation step. Old in-flight instances skip this.
  if (ctx.isPatched("add-validation-step")) {
    yield ctx.callActivity(validateOrder, result);
  }

  yield ctx.callActivity(shipOrder, result);
}

Acceptance Criteria

• WorkflowContext.isPatchEnabled(patchName: string): boolean is implemented
• In-flight instances that have never seen the patch name return false
• New instances or instances that haven't yet reached the patch point return true
• The patch is recorded in the orchestration history so subsequent replays are deterministic
• Unit and e2e tests cover both old-instance and new-instance paths
• Documentation with usage examples