feat: update version handling and dependencies for improved versionchecks

[isaaclins]

This pull request introduces improvements to how the application determines and displays its build version, and refines the update checking logic to more accurately compare versions. These changes enhance the reliability of update notifications and ensure that the correct version information is shown in the UI.

Versioning improvements:

• Added a new constant BUILD_VERSION to psst-core/src/lib.rs that uses the RELEASE_VERSION environment variable if available, falling back to CARGO_PKG_VERSION otherwise, ensuring more accurate version reporting.
• Updated the UI in psst-gui/src/ui/preferences.rs to display psst_core::BUILD_VERSION instead of the static package version, so the user always sees the actual build version.

Update checking logic enhancements:

• Changed CURRENT_VERSION in psst-gui/src/data/update_checker.rs to reference psst_core::BUILD_VERSION, aligning update checks with the displayed version.
• Improved the version comparison logic in UpdateInfo::is_newer_version() to use semantic versioning when possible, falling back to string comparison for date-based versions, making update detection more robust.
• Added the semver crate to dependencies and imported it in psst-gui/src/data/update_checker.rs to support semantic version parsing and comparison. [1] [2]

[isaaclins]

should be okay