add: Hybrid / FFT-Enhanced Transfer Baseline

[andrewwu13]

Description of Changes

• combined pretrained cnn with custome fft branch
• concatenates both feature vectors
• trains a small classifier head end-to-end

Linked Issue

Closes #24

Type of Change

• Model: Machine learning model development, training, or architecture changes
• Data: Dataset management, preprocessing, or data pipeline work
• Web: Frontend dashboard or web interface development
• API: Backend API development or FastAPI endpoints
• Research: Experimental features or research exploration
• Documentation: Documentation updates or technical writing
• Bug Fix: Fixes a bug or issue
• Refactor: Code cleanup or optimization without functional changes

Screenshots/Results

Assignment Instructions

• Assigned lukhsaankumar as the reviewer
• Added yourself as the assignee (add multiple people if multiple contributors worked on this PR)

Additional Comments