feat(error_code): added error code as enum

[giuliastf]

Description
This pull request introduces a new standardized error code enumeration (UiPathErrorCode) for UiPath runtime errors and updates all error handling logic to use this enum instead of raw string codes.

Fix issue

[Copilot]

Pull Request Overview

This pull request introduces standardized error code handling by creating a UiPathErrorCode enum and updating all error handling logic to use enum values instead of raw string codes. This change improves type safety and maintainability of error handling across the UiPath runtime.

• Added UiPathErrorCode enum with standardized error codes for different categories (entrypoint, execution, HITL, etc.)
• Updated UiPathRuntimeError constructor to accept UiPathErrorCode enum instead of raw strings
• Replaced all string-based error codes throughout the codebase with corresponding enum values

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/uipath/_cli/_runtime/_contracts.py	Added UiPathErrorCode enum definition and updated UiPathRuntimeError constructor to use enum type
src/uipath/_cli/_runtime/_script_executor.py	Updated all error instantiations to use UiPathErrorCode enum values
src/uipath/_cli/_runtime/_runtime.py	Updated error handling to use UiPathErrorCode enum
src/uipath/_cli/_runtime/_hitl.py	Updated HITL-related error handling to use enum values
pyproject.toml	Bumped version from 2.1.72 to 2.1.73

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}