Fix: Move Pinecone index and namespace to environment variables

[Rinta13795]

Fix: Move Pinecone index and namespace to environment variables

Description

Problem:

• models/NewsModel.py hardcoded index_name as 'cybernews-hybrid-test-2'
• models/NewsModel.py hardcoded namespace as 'c2si'
• db_update/Update.py hardcoded namespace as 'c2si'
• Prevented multi-environment deployment

Solution:

• Read PINECONE_INDEX_NAME from env (default: 'cybernews-index')
• Read PINECONE_NAMESPACE from env (default: 'c2si')
• Added both variables to .env.example
• Maintains backward compatibility

Related Issue

Fixes #111

Motivation and Context

This change allows the project to be deployed in multiple environments (dev/staging/prod) without code modifications. Users can now configure different Pinecone indexes and namespaces via environment variables.

How Has This Been Tested?

• Verified environment variable loading in both models/NewsModel.py and db_update/Update.py
• Tested backward compatibility with default values
• Both online queries and offline updates are now configurable

Types of changes

• Bug fix (non-breaking change which fixes an issue)

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 read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.