fix(amazonq): zip entry contains invalid characters

[ctlai95]

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)

Description

Code reviews sometimes fail due to invalid zip entry path error for certain workspace configurations.

Root cause:
The condition selectedFile.path.startsWith(projectRoot.path) string comparison incorrectly returns true if the selected file is not in the projectRoot but has a partial path prefix match of the projectRoot.

For example:

projectRoot.path = "/home/user/project"
selectedFile.path = "/home/user/project2/some/file.java"

Solution:
Use built-in VirtualFile util method to check if the file is actually within the projectRoot.

Checklist

• My code follows the code style of this project
• I have added tests to cover my changes
• A short description of the change has been added to the CHANGELOG if the change is customer-facing in the IDE.
• I have added metrics for my changes (if required)

License

I confirm that my contribution is made under the terms of the Apache 2.0 license.