Slim requirements: remove torch/chronos/streamlit for API build

backend/requirements.txt

@@ -1,7 +1,7 @@
-# Backend-specific dependencies (on top of root requirements.txt)
+# Backend-specific dependencies
 fastapi>=0.115.0
 uvicorn[standard]>=0.34.0
 pydantic>=2.0
 slowapi>=0.2.0
 PyJWT>=2.8.0
-sentry-sdk[fastapi]>=2.0  # optional: set SENTRY_DSN to enable
+sentry-sdk[fastapi]>=2.0

requirements.txt

@@ -1,18 +1,10 @@
-# Photosynthesis Prediction Model - dependencies
-# Install: pip install -r requirements.txt
-
-pandas==2.3.3
-numpy==2.4.2
-scikit-learn==1.8.0
-matplotlib==3.10.8
-seaborn==0.13.2
-requests==2.32.5
-python-dotenv==1.2.1
-streamlit==1.54.0
-plotly==6.5.2
+# API-only dependencies (slim — no torch/chronos/streamlit)
+pandas>=2.0
+numpy>=1.26
+scikit-learn>=1.3
+requests>=2.31
+python-dotenv>=1.0
 xgboost>=2.0
 pvlib>=0.10.0
 astral>=3.2
-chronos-forecasting>=2.0
-torch>=2.0
 google-genai>=1.0