Add WOLFHSM_CFG_CANCEL_API for opt-in cancellation support

[jackctj117]

Fix for #168 (review)

• Revert broad WOLFHSM_CFG_TEST_CLIENT_ONLY_TCP gating
• Add WOLFHSM_CFG_CANCEL_API to compile out cancellation by default
• Properly guard test server instrumentation with WOLFHSM_CFG_IS_TEST_SERVER
• Disabled serverDelay

[Copilot]

Pull Request Overview

This PR introduces an optional cancellation API feature through the WOLFHSM_CFG_CANCEL_API configuration flag. The changes revert previous broad gating and implement proper feature-specific guarding for cancellation functionality.

• Add WOLFHSM_CFG_CANCEL_API configuration flag to make cancellation support opt-in
• Guard cancellation-related code, structures, and functions with the new configuration flag
• Replace broad WOLFHSM_CFG_TEST_CLIENT_ONLY_TCP gating with more specific WOLFHSM_CFG_IS_TEST_SERVER guards for test instrumentation

Reviewed Changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
wolfhsm/wh_settings.h	Adds documentation for the new WOLFHSM_CFG_CANCEL_API configuration flag
wolfhsm/wh_server.h	Guards server-side cancellation fields and functions with WOLFHSM_CFG_CANCEL_API
wolfhsm/wh_client.h	Guards client-side cancellation fields and functions with WOLFHSM_CFG_CANCEL_API
test/wh_test_crypto.c	Updates test code to use proper feature guards and temporarily disables server delay
src/wh_server_crypto.c	Guards cancellation handling in crypto operations with WOLFHSM_CFG_CANCEL_API
src/wh_server.c	Guards server cancellation functions and message handling with WOLFHSM_CFG_CANCEL_API
src/wh_client_crypto.c	Guards cancellable response handling with WOLFHSM_CFG_CANCEL_API
src/wh_client.c	Guards client cancellation functions with WOLFHSM_CFG_CANCEL_API

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