Convert UUID to string for session and chat identifiers

[hello-shaharia-lab]

Replaced usage of uuid.UUID with string for session and chat UUIDs across the codebase. Updated relevant methods, tests, and mocks to handle the new string format, improving flexibility and compatibility.

Related Issue(s)

• Fixes #

Description

Changes Made

Testing

• Added new unit tests
• Manually tested (describe steps below)

Checklist

• My code follows the project's coding style guidelines (CONTRIBUTING.md).
• I have added tests that prove my fix is effective or that my feature works.
• I have updated the documentation accordingly (if applicable).
• I have added an entry to CHANGELOG.md (if applicable).
• All new and existing tests passed.

Additional Context

[sonarqubecloud]

Quality Gate failed

Failed conditions
23.1% Coverage on New Code (required ≥ 80%)

See analysis details on SonarQube Cloud