Optimization: Move email-validator to end of Dockerfile to preserve heavy ML layer cache

Dockerfile

@@ -22,7 +22,7 @@ COPY requirements.txt .
 RUN pip install --no-cache-dir --upgrade pip
 
 # Step 1: Core Framework
-RUN pip install --no-cache-dir fastapi "uvicorn[standard]" python-multipart python-dotenv pydantic "pydantic-settings" email-validator motor "passlib[bcrypt]" PyJWT google-generativeai
+RUN pip install --no-cache-dir fastapi "uvicorn[standard]" python-multipart python-dotenv pydantic "pydantic-settings" motor "passlib[bcrypt]" PyJWT google-generativeai
 
 # Step 2: Heavy ML Engines (CPU Only)
 RUN pip install --no-cache-dir torch torchaudio torchvision --index-url https://download.pytorch.org/whl/cpu
@@ -40,7 +40,7 @@ RUN pip install --no-cache-dir "pyannote.audio>=3.1.0"
 RUN pip install --no-cache-dir c2pa-python
 
 # Step 7: Final Misc
-RUN pip install --no-cache-dir "protobuf~=4.25.3" python-magic
+RUN pip install --no-cache-dir "protobuf~=4.25.3" python-magic email-validator
 
 COPY . .