Remove unused langchain-ollama dependency from setup.py

[chigwell]

User Story
As a software maintainer,
I want to remove unused dependencies from the project's package configuration
so that we reduce technical debt and avoid maintaining unnecessary components.

Background
The setup.py file currently declares langchain-ollama==0.3.0 in its install_requires list, but this dependency isn't referenced in any project code (including main.py, test_eknowledge.py, or other modules). This creates three key issues:

1. Package Bloat: Unused dependencies increase installation size and potential attack surface
2. Dependency Conflicts: May cause version clashes with other required packages
3. Maintenance Overhead: Requires unnecessary version tracking and security updates

Acceptance Criteria

• Remove langchain-ollama from install_requires in setup.py
• Verify through these validation steps:
  • Run pip install -e . and confirm successful installation
  • Execute pytest tests/ to ensure no missing dependency errors
  • Check all import statements in main.py, test_eknowledge.py, and related modules for accidental usage
• Confirm reduced package size by comparing pip show eknowledge output before/after change
• Ensure documentation (README.md) doesn't reference langchain-ollama in installation instructions