fix: Preserve original URL parsing error cause in getHostAddress()

[YunchuWang]

Fixes #191

Problem

getHostAddress() in DurableTaskAzureManagedClientOptions catches URL parsing errors and re-throws a new Error with a descriptive message, but drops the original error. This makes it difficult to diagnose why a specific endpoint URL is invalid.

Changes

• Change the catch block to preserve the original error as the cause using { cause: e }
• Consistent with the error wrapping convention used elsewhere in the codebase (e.g., pb-helper.util.ts:434)

[Copilot]

Pull request overview

This PR improves debuggability of Azure Managed SDK endpoint configuration by preserving the original URL parsing error when getHostAddress() rejects an invalid endpoint, aligning with existing error-wrapping patterns in the repo.

Changes:

• Preserve the original URL parsing exception by rethrowing with new Error(..., { cause: e }) in getHostAddress().
• Add a unit test asserting that the thrown error includes a defined cause.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
packages/durabletask-js-azuremanaged/src/options.ts	Wrap URL parsing failures with { cause } so the original parsing error is retained.
packages/durabletask-js-azuremanaged/test/unit/options.spec.ts	Adds a test to validate that getHostAddress() preserves the underlying parsing error as cause.

[Copilot]

The test calls fail("Expected getHostAddress to throw"), but this repo's Jest setup uses the default jest-circus runner (no jest-jasmine2), where fail is not a guaranteed global and can cause a ReferenceError, failing the suite. Prefer throwing an Error in that branch (or structure the test to capture the thrown error without relying on fail).

Suggested change

	fail("Expected getHostAddress to throw");
	throw new Error("Expected getHostAddress to throw");