Improved GUI to clarify Passphrase Field (Issue #2193)

[shreyamali01]

Description

This pull request improves the user interface while creating a new repository by providing clearer instructions for the passphrase field. The improvement here addresses the user confusion by explicitly stating the purpose of passphrase (for encryption).

Related Issue

Fixes #2193 - Clarifies the passphrase field when creating a new repository.

Motivation and Context

When creating a new repository in Vorta, the users were unclear about the purpose of passphrase field. This change explicitly states the purpose of passphrase. This is crucial because without this passphrase users cannot decrypt their backup.

How Has This Been Tested?

The changes were tested by :

• Launching the "Create New Repository" dialog and verifying that the passphrase field is correctly labeled.
• Ensuring tooltip now clearly states the importance of passphrase and recommends to store it.
• Testing the GUI for proper layout and sectioning under new "Encryption" header.

Screenshots:

Before

After

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• I have read the CONTRIBUTING guide.
• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.

I provide my contribution under the terms of the license of this repository and I affirm the Developer Certificate of Origin.