Fix script cancellation with new dialog on Linux

This commit improves the management of script execution process by
enhancing the way terminal commands are handled, paving the way for
easier future modifications and providing clearer feedback to users when
scripts are cancelled.

Previously, the UI displayed a generic error message which could lead to
confusion if the user intentionally cancelled the script execution. Now,
a specific error dialog will appear, improving the user experience by
accurately reflecting the action taken by the user.

This change affects code execution on Linux where closing GNOME terminal
returns exit code `137` which is then treated by script cancellation by
privacy.sexy to show the accurate error dialog. It does not affect macOS
and Windows as curret commands result in success (`0`) exit code on
cancellation.

Additionally, this update encapsulates OS-specific logic into dedicated
classes, promoting better separation of concerns and increasing the
modularity of the codebase. This makes it simpler to maintain and extend
the application.

Key changes:

- Display a specific error message for script cancellations.
- Refactor command execution into dedicated classes.
- Improve file permission setting flexibility and avoid setting file
  permissions on Windows as it's not required to execute files.
- Introduce more granular error types for script execution.
- Increase logging for shell commands to aid in debugging.
- Expand test coverage to ensure reliability.
- Fix error dialogs not showing the error messages due to incorrect
  propagation of errors.

Other supported changes:

- Update `SECURITY.md` with details on script readback and verification.
- Fix a typo in `IpcRegistration.spec.ts`.
- Document antivirus scans in `desktop-vs-web-features.md`.

docs/desktop/desktop-vs-web-features.md

@@ -8,10 +8,8 @@ This table outlines the differences between the desktop and web versions of `pri
 | [Offline usage](#offline-usage) | 🟢 Available | 🟡 Partially available |
 | [Auto-updates](#auto-updates) | 🟢 Available | 🟢 Available |
 | [Logging](#logging) | 🟢 Available | 🔴 Not available |
-| [Script execution](#script-execution) | 🟢 Available | 🔴 Not available |
-| [Error handling](#error-handling) | 🟢 Advanced | 🟡 Limited |
-| [Native dialogs](#native-dialogs) | 🟢 Available | 🔴 Not available |
 | [Secure script execution/storage](#secure-script-executionstorage) | 🟢 Available | 🔴 Not available |
+| [Native dialogs](#native-dialogs) | 🟢 Available | 🔴 Not available |
 
 ## Feature descriptions
 
@@ -53,7 +51,7 @@ Log file locations vary by operating system:
 
 > 💡 privacy.sexy provides scripts to securely erase these logs.
 
-### Script execution
+### Secure script execution/storage
 
 The desktop version of privacy.sexy enables direct script execution, providing a seamless and integrated experience.
 This direct execution capability isn't available in the web version due to inherent browser restrictions.
@@ -69,31 +67,27 @@ These locations vary based on the operating system:
 
 > 💡 privacy.sexy provides scripts to securely erase your script execution history.
 
-### Error handling
+**Script antivirus scans:**
 
-The desktop version of privacy.sexy features advanced error handling capabilities.
-It employs robust and reliable execution strategies, including self-healing mechanisms, and provides guidance and troubleshooting information to resolve issues effectively.
-In contrast, the web version has more basic error handling due to browser limitations and the nature of web applications.
+To enhance system protection, the desktop version of privacy.sexy automatically verifies the security of script
+execution files by reading them back.
+This process triggers antivirus scans to verify that scripts are safe before the execution.
 
-### Native dialogs
-
-The desktop version uses native dialogs, offering more features and reliability compared to the browser's file system dialogs.
-These native dialogs provide a more integrated and user-friendly experience, aligning with the operating system's standard interface and functionalities.
-
-### Secure script execution/storage
-
-**Integrity checks:**
+**Script integrity checks:**
 
 The desktop version of privacy.sexy implements robust integrity checks for both script execution and storage.
 Featuring tamper protection, the application actively verifies the integrity of script files before executing or saving them.
 If the actual contents of a script file do not align with the expected contents, the application refuses to execute or save the script.
 This proactive approach ensures only unaltered and verified scripts undergo processing, thereby enhancing both security and reliability.
-Due to browser constraints, this feature is absent in the web version.
 
 **Error handling:**
 
+The desktop version of privacy.sexy features advanced error handling capabilities.
 In scenarios where script execution or storage encounters failure, the desktop application initiates automated troubleshooting and self-healing processes.
-It also guides users through potential issues with filesystem or third-party software, such as antivirus interventions.
-Specifically, the application is capable of identifying when antivirus software blocks or removes a script, providing users with tailored error messages
-and detailed resolution steps. This level of proactive error handling and user guidance enhances the application's security and reliability,
-offering a feature not achievable in the web version due to browser limitations.
+It employs robust and reliable execution strategies, including self-healing mechanisms, and provides guidance and troubleshooting information to resolve issues effectively.
+This proactive error handling and user guidance enhances the application's security and reliability.
+
+### Native dialogs
+
+The desktop version uses native dialogs, offering more features and reliability compared to the browser's file system dialogs.
+These native dialogs provide a more integrated and user-friendly experience, aligning with the operating system's standard interface and functionalities.