fix: updated Dockerfile with proper gated repo authentication

Dockerfile

@@ -2,12 +2,16 @@ FROM python:3.12-slim
 
 WORKDIR /app
 
-# Layer 1: Install dependencies (Cached)
+# Layer 1: Install dependencies
 COPY requirements.txt .
 RUN pip install --no-cache-dir -r requirements.txt
 
-# Layer 2: Pre-cache AI Models (Fixed Syntax)
-RUN python -c "\
+# Layer 2: Pre-cache AI Models (Authenticated for Gated Repos)
+RUN --mount=type=secret,id=HF_TOKEN,mode=0444,required=true \
+    python -c "\
+import os; \
+from huggingface_hub import login; \
+login(token=open('/run/secrets/HF_TOKEN').read().strip()); \
 from sentence_transformers import SentenceTransformer, CrossEncoder; \
 SentenceTransformer('BAAI/bge-m3', cache_folder='/app/models'); \
 CrossEncoder('BAAI/bge-reranker-base', cache_dir='/app/models'); \
@@ -16,7 +20,7 @@ AutoTokenizer.from_pretrained('ai4bharat/indictrans2-en-indic-dist-200M', trust_
 AutoModelForSeq2SeqLM.from_pretrained('ai4bharat/indictrans2-en-indic-dist-200M', trust_remote_code=True, cache_dir='/app/models/indictrans2'); \
 print('✓ All Embedding, Reranker, and IndicTrans2 models cached')"
 
-# Layer 3: Copy application code (Updates instantly on code changes)
+# Layer 3: Copy application code
 COPY . .
 
 EXPOSE 7860