[Feature] Improve test stability with safer access, clearer errors, and better assertions

[EmmaYuan1015]

Improve test reliability and debuggability with safer optional access, clearer error handling, awaited async actions, and more informative assertions/logging.

• Safer property access: this.currentTest?.title ?? "unknown" avoids runtime errors.
• Better error handling: Differentiates between Error objects and other types, providing clearer error messages.
• Asynchronous operation guidelines: await actionButton.click() ensures the click operation completes before continuing.
• More useful assertion messages: All assertions have descriptive messages added, facilitating quick problem location when debugging failed test cases.
• Improved logging output: Includes actual values ​​in assertion messages for easier problem troubleshooting.