Pin exact dependency versions in requirements.txt

[ezhil-003]

requirements.txt currently uses unpinned dependencies, which makes installs non-reproducible and increases drift across environments.

Current direct dependencies are:

rich==14.3.3
requests==2.32.5
beautifulsoup4==4.14.3
urllib3==2.6.3

These versions were verified from the local virtual environment on April 9, 2026 with Python 3.14.0.

• Replace unpinned entries in requirements.txt with exact versions.
• Keep the dependency list limited to packages the project directly imports.