fix: reserved keywords in query fields

[jagadeesh-00]

Description

• When query fields contains any reserved keywords, the query is giving 400 error with below ValidationException

Related Issues

Issue: #166

How Has This Been Tested

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

• 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.

Screenshots (if appropriate)

[cursor]

Bug: Projection Alias Case Sensitivity Issue

The new projection alias generation creates non-unique aliases by uppercasing field names. This causes ExpressionAttributeNames collisions when projection fields differ only by case, or when they match existing aliases from where conditions or partition/sort keys. These overwrites lead to incorrect field projections or break KeyConditionExpression/FilterExpression references, causing data loss or query failures.