rewrite: switch from instaloader to Instagram Private API

instaloader blocked by Instagram GraphQL 403. Using mobile API instead:
- i.instagram.com/api/v1 endpoints (same as Android app)
- Direct cookie loading from cookies.txt
- Stories, posts, albums, videos
- Random delays between requests
- Removed instaloader dependency, using requests directly

Dockerfile

@@ -3,7 +3,7 @@ FROM python:3.12-slim
 WORKDIR /app
 
 RUN apt-get update && \
-    apt-get install -y --no-install-recommends ffmpeg && \
+    apt-get install -y --no-install-recommends curl && \
     rm -rf /var/lib/apt/lists/*
 
 COPY requirements.txt .
@@ -11,6 +11,6 @@ RUN pip install --no-cache-dir -r requirements.txt
 
 COPY . .
 
-RUN mkdir -p /data/downloads /data/session
+RUN mkdir -p /data/downloads
 
 CMD ["python", "bot.py"]